• The upper limb is a freely movable structure with many joints.
• It is attached to the trunk at the shoulder joint.
• Its main function is to move the hand into positions where it can handle and manipulate objects.
• The hand is a highly developed organ.
• It can grasp objects in both coarse (strong) and fine (precise) ways.
• The thumb is especially important because it can move opposite to the other fingers like a pincer.
• This opposable thumb allows the tip of the thumb to touch the tips of the other fingers.
• The upper limb is divided into the shoulder region, the arm, the cubital fossa, the forearm, the wrist, and the hand.
• The arm, forearm, and hand are divided into compartments that work as separate units.
• Each compartment has its own muscles.
• These muscles perform both group actions and individual actions.
• Each compartment has its own nerve supply.
• Each compartment has its own blood supply.
• Physicians commonly see pain in the upper limb.
• Fractures are common injuries of the upper limb.
• Dislocations are common injuries of the upper limb.
• Nerve injuries are also common in the upper limb.
• Wrist injuries need special attention.
• Hand injuries also need special attention.
• Preserving as much thumb function as possible is very important.

KEY CONCEPT

• The upper limb mainly positions the hand to perform different tasks.
• The hand can perform both powerful and delicate movements.
• The opposable thumb is the key feature that makes the hand highly functional.
• The upper limb is organized into different regions and compartments, each with its own muscles, nerves, and blood supply.
• Thumb function should be preserved as much as possible after wrist or hand injuries.

Conceptual Examples

• Holding a hammer = coarse (strong) grasp.
• Holding a pen = fine (precise) grasp.
• Picking up a small coin by touching the thumb to the index finger = opposable thumb (pincer action).

OSTEOLOGY

• The upper limb is part of the appendicular skeleton.
• The bones of the upper limb are the clavicle, scapula, humerus, ulna, radius, carpal bones, metacarpal bones, and phalanges.
• The clavicle and scapula together form the shoulder girdle.
• The humerus forms the arm.
• The radius and ulna form the forearm.
• The carpal bones form the wrist.
• The metacarpals and phalanges form the hand.
• This section gives a complete description of the bones of the upper limb and their important features.
• Do not learn these bones by only memorizing difficult words.
• Try to understand the meaning of the anatomical terms.
• For example, understand the difference between a tubercle and a tuberosity.
• Understanding the terms helps you better understand the anatomy.
• Most importantly, ask functional questions while examining the bones.
• Ask yourself whether the bone is from the right side or the left side.
• Ask which bone or structure articulates with this area.
• Ask which muscle, ligament, or other structure attaches to this area.
• Ask whether this structure can be felt (palpated).
• Ask whether this structure can be identified on a standard radiographic image.
• Ask whether there are any important nerves or blood vessels related to this region or structure.

KEY CONCEPT

• The upper limb is made up of the clavicle, scapula, humerus, ulna, radius, carpal bones, metacarpals, and phalanges.
• The shoulder girdle is formed by the clavicle and scapula.
• The humerus forms the arm, the radius and ulna form the forearm, the carpals form the wrist, and the metacarpals and phalanges form the hand.
• Learning the meaning of anatomical terms is better than only memorizing names.
• Always study bones by asking functional questions about side, articulations, attachments, palpation, X-ray appearance, and neurovascular relations.

Conceptual Examples

• Right or left bone: Identify whether a humerus belongs to the right or left upper limb.
• Articulation: The humerus articulates with the scapula at the shoulder joint.
• Attachment: Muscles attach to different bony prominences.
• Palpation: The clavicle can be easily felt under the skin.
• Radiograph: The humerus can be identified on a standard X-ray.
• Neurovascular relation: Important nerves and blood vessels pass close to some upper limb bones.

Clavicle

• The clavicle is also called the collar bone.
• The word clavicul- is Latin for “key.”
• The clavicle is located between the sternum and the scapula.
• It lies horizontally across the root of the neck.
• It is roughly S-shaped.
• It looks like a large, old-style key.
• The clavicle acts as a light strut.
• It connects the upper limb to the thorax.
• It allows the upper limb to move freely away from the trunk.
• The clavicle is the first bone to begin ossification.
• The clavicle is just under the skin (subcutaneous).
• It can be easily felt (palpated) along its entire length.
• The sternal extremity (Fig. 3.1) is the blunt, thick, proximal (medial) end of the clavicle.
• It articulates with the clavicular notch of the sternum.
• This joint is a compound synovial joint.
• The joint contains an articular disc.
• The acromial extremity is the flattened distal (lateral) end of the clavicle.
• It articulates with the acromion process of the scapula.
• The conoid tubercle is a small, rough elevation on the inferior surface near the acromial end.
• The word cono- is Greek for “pine cone.”
• The conoid tubercle provides attachment for the conoid ligament.
• The conoid ligament is part of the coracoclavicular ligament.
• The important muscles and ligaments attached to the clavicle are shown in Figures 3.1 and 3.2.

KEY CONCEPT

• The clavicle is the collar bone connecting the upper limb to the thorax.
• It is S-shaped and lies between the sternum and the scapula.
• The sternal extremity (Fig. 3.1) forms a compound synovial joint with the sternum.
• The acromial extremity articulates with the acromion of the scapula.
• The conoid tubercle provides attachment for the conoid ligament of the coracoclavicular ligament.
• The muscles and ligaments attached to the clavicle are shown in Figures 3.1 and 3.2.

Conceptual Examples

• The sternal extremity is the end of the clavicle that joins the sternum.
• The acromial extremity is the end of the clavicle that joins the scapula.
• The conoid tubercle acts as an attachment point where the conoid ligament is fixed.

Figure Number: Fig. 3.1 (mentioned with the sternal extremity), Figures 3.1 and 3.2 (mentioned for muscle and ligament attachments).

Clinical Notes

Clavicle Fracture

• The clavicle acts as a strut that keeps the arm away from the trunk.
• This allows the arm to move freely.
• The clavicle is the only bony connection between the upper limb and the axial skeleton.
• It transfers all forces from the upper limb to the trunk.
• Because of its position, the clavicle is easily injured by trauma.
• It is the most commonly fractured bone in the body.
• A clavicle fracture usually happens after a fall on the shoulder.
• It can also occur after a fall on an outstretched hand.
• The force travels along the clavicle.
• The clavicle usually breaks at its weakest point.
• The weakest point is the junction of the middle one-third and outer one-third.
• After the fracture, the lateral (outer) fragment moves downward because of the weight of the arm.
• The lateral fragment is also pulled medially (toward the body) and forward.
• This pull is produced by the strong adductor muscles of the shoulder joint.
• The pectoralis major is the main muscle responsible for this pull.
• The medial (inner) fragment is pulled upward.
• The sternocleidomastoid muscle causes this upward tilt.
• The supraclavicular nerves lie very close to the clavicle.
• After a clavicle fracture, these nerves may become involved in callus formation.
• This nerve involvement may cause persistent pain over the side of the neck.

KEY CONCEPT

• The clavicle keeps the arm away from the trunk and transfers forces from the upper limb to the axial skeleton.
• It is the most commonly fractured bone because it is easily exposed to trauma.
• Fractures usually occur at the junction of the middle one-third and outer one-third.
• After a fracture:
  • The lateral fragment moves downward, medially, and forward.
  • The medial fragment moves upward.
• Involvement of the supraclavicular nerves during healing may cause long-lasting pain on the side of the neck.

Conceptual Examples

• Falling directly on the shoulder → Force travels through the clavicle → Fracture occurs at its weakest point.
• After the fracture, the arm hangs down because the lateral fragment is pulled downward by the weight of the arm.
• The sternocleidomastoid muscle pulls the medial fragment upward.
• If the supraclavicular nerves become trapped in the healing callus, pain may continue on the side of the neck.

Clinical Notes

Clavicle Fracture

• The clavicle acts as a strut that keeps the arm away from the trunk.
• This allows the arm to move freely.
• The clavicle is the only bony connection between the upper limb and the axial skeleton.
• It transfers all forces from the upper limb to the trunk.
• Because of its position, the clavicle is easily injured by trauma.
• It is the most commonly fractured bone in the body.
• A clavicle fracture usually occurs after a fall on the shoulder.
• It can also occur after a fall on an outstretched hand.
• The force travels through the clavicle.
• The clavicle usually breaks at its weakest point.
• The weakest point is the junction of the middle one-third and outer one-third.
• After the fracture, the lateral (outer) fragment moves downward because of the weight of the arm.
• The lateral fragment is also pulled medially (toward the body) and forward.
• This pull is caused by the strong adductor muscles of the shoulder joint.
• The pectoralis major is the main muscle responsible for this pull.
• The medial (inner) fragment is pulled upward.
• The sternocleidomastoid muscle causes this upward movement.
• The supraclavicular nerves lie very close to the clavicle.
• After a clavicle fracture, these nerves may become involved in callus formation.
• This nerve involvement may cause persistent pain on the side of the neck.

KEY CONCEPT

• The clavicle keeps the arm away from the trunk and transfers forces from the upper limb to the axial skeleton.
• It is the most commonly fractured bone because it is easily exposed to trauma.
• Most fractures occur at the junction of the middle one-third and outer one-third.
• After a fracture:
  • The lateral fragment moves downward, medially, and forward.
  • The medial fragment moves upward.
• During healing, involvement of the supraclavicular nerves may cause long-lasting pain on the side of the neck.

Conceptual Examples

• Fall on the shoulder → Force passes through the clavicle → Fracture occurs at the weakest point.
• Weight of the arm → Pulls the lateral fragment downward.
• Pectoralis major muscle → Pulls the lateral fragment medially and forward.
• Sternocleidomastoid muscle → Pulls the medial fragment upward.
• Supraclavicular nerves trapped in healing callus → Persistent pain on the side of the neck.

Scapula

• The scapula is also called the shoulder bone.
• The word scapul- is Latin for “shoulder blade.”
• The scapula is a large, flat, triangular bone.
• It lies on the posterior chest wall between the 2nd and 7th ribs.
• It articulates with the acromial end of the clavicle.
• It also articulates with the head of the humerus.
• The main features of the scapula are:
  • Three borders – superior, medial, and lateral.
  • Three angles – superior, inferior, and lateral.
  • Two surfaces – dorsal and costal.
  • Three bony processes – spine, acromion, and coracoid (Fig. 3.3).
• The superior border is the short, thin upper edge of the scapula.
• The scapular notch is present on the lateral part of the superior border near the base of the coracoid process.
• The superior transverse scapular ligament bridges the scapular notch.
• The suprascapular artery passes above the ligament.
• The suprascapular nerve passes below the ligament.
• Remember: Army goes over the bridge; Navy goes under the bridge.
• The medial (vertebral) border is the long edge nearest the vertebral column.
• The lateral (axillary) border is the thick edge nearest the axilla.
• The junction of the superior and medial borders forms the superior angle.
• The junction of the medial and lateral borders forms the inferior angle.
• The inferior angle can be easily felt (palpated) in a living person.
• It marks the level of the 7th rib.
• It also marks the level of the spine of the 7th thoracic vertebra.
• The junction of the superior and lateral borders forms the lateral angle.
• The lateral angle is the thickest and most complex part of the scapula.
• It mainly consists of the head of the scapula.
• The head is connected to the rest of the scapula by the neck of the scapula.
• The lateral surface of the head forms the glenoid cavity (glenoid fossa).
• The word glen- is Greek for “pit” or “socket.”
• The glenoid cavity articulates with the head of the humerus.
• The glenoid labrum is a fibrocartilage ring around the glenoid cavity.
• It broadens and deepens the joint cavity.
• The supraglenoid tubercle is located above the glenoid cavity near the base of the coracoid process.
• The infraglenoid tubercle is located immediately below the glenoid cavity.
• The dorsal (posterior) surface is divided into two unequal regions by the spine of the scapula.
• The area above the spine is the supraspinous fossa.
• The area below the spine is the infraspinous fossa.
• The spine is a large triangular ridge.
• It extends laterally from the medial border to the acromion process.
• The lateral end of the spine joins the neck of the scapula.
• This forms the spinoglenoid (greater scapular) notch.
• The notch connects the supraspinous and infraspinous fossae.
• The suprascapular nerve and vessels pass through this notch between the two fossae.
• The acromion is the broad, flat lateral extension of the spine.
• The word acromi- is Greek for “point of the shoulder.”
• The acromion forms the easily felt tip of the shoulder.
• It partly covers the glenoid cavity.
• It articulates with the clavicle at the acromioclavicular joint.
• The costal (ventral, anterior) surface lies against the posterior surface of the rib cage.
• Most of this surface forms the subscapular fossa.
• The coracoid process is a thick, beak-shaped projection.
• The word coraco- is Greek for “like a crow’s beak.”
• It projects anterolaterally from the junction of the neck and the lateral end of the superior border.
• The coracoid process can be felt by applying deep pressure through the anterior part of the deltoid muscle below the lateral end of the clavicle.
• The main muscles and ligaments attached to the scapula are shown in Figures 3.1 and 3.3.

KEY CONCEPT

• The scapula is a flat triangular bone located on the posterior chest wall.
• It articulates with the clavicle and the humerus.
• It has 3 borders, 3 angles, 2 surfaces, and 3 processes (Fig. 3.3).
• The glenoid cavity forms the socket for the head of the humerus.
• The glenoid labrum makes the socket broader and deeper.
• The spine divides the dorsal surface into the supraspinous and infraspinous fossae.
• The acromion forms the tip of the shoulder and articulates with the clavicle.
• The coracoid process is a beak-like projection for important muscle and ligament attachments.
• Remember: Suprascapular artery passes over the superior transverse scapular ligament, while the suprascapular nerve passes under it.

Conceptual Examples

• Feel the tip of your shoulder → You are touching the acromion.
• Feel the lower point of your shoulder blade on your back → This is the inferior angle.
• The glenoid cavity acts like a shallow socket, while the head of the humerus acts like a ball, together forming the shoulder joint.
• Think of the superior transverse scapular ligament as a bridge:
  • Army (artery) goes over the bridge.
  • Navy (nerve) goes under the bridge.

Figure Numbers: Fig. 3.3 (main features of the scapula); Figures 3.1 and 3.3 (muscle and ligament attachments).

Clinical Notes

Scapular Fractures

• Scapular fractures usually occur because of severe trauma.
• They are commonly seen in run-over accident victims.
• They are also common in people involved in motor vehicle crashes.
• Scapular fractures are usually associated with fractured ribs.
• Most scapular fractures need little direct treatment.
• The muscles on the anterior and posterior surfaces of the scapula hold the broken pieces in place (splint the fragments).

Dropped Shoulder and Winged Scapula

• The scapula is kept in its normal position on the posterior chest wall by the tone and balance of its attached muscles.
• If one of these muscles becomes paralyzed, this balance is disturbed.
• Dropped shoulder occurs due to paralysis of the trapezius muscle.
• Winged scapula (Fig. 3.4) occurs due to paralysis of the serratus anterior muscle.
• In winged scapula, the scapula projects backward like a wing.
• These muscle imbalances can be detected by a careful physical examination.

KEY CONCEPT

• Scapular fractures are usually caused by severe trauma.
• They are commonly associated with rib fractures.
• Most scapular fractures heal with minimal direct treatment because surrounding muscles stabilize the bone fragments.
• The normal position of the scapula depends on the balance of its muscles.
• Trapezius paralysis → Dropped shoulder.
• Serratus anterior paralysis → Winged scapula (Fig. 3.4).
• Careful physical examination helps identify these muscle imbalances.

Conceptual Examples

• High-speed road traffic accident → Severe trauma → Scapular fracture, often with rib fractures.
• Trapezius muscle paralysis → Shoulder hangs lower than normal → Dropped shoulder.
• Serratus anterior paralysis → Medial border of the scapula sticks out like a wing when pushing against a wall → Winged scapula (Fig. 3.4).

Figure Number: Fig. 3.4 (Winged scapula).

Humerus

• The humerus is the bone of the arm (brachium).
• The word humer- is Latin for “shoulder.”
• It is the longest bone of the upper limb.
• Proximally, it articulates with the glenoid cavity of the scapula at the glenohumeral (shoulder) joint.
• Distally, it articulates with the head of the radius and the trochlear notch of the ulna at the elbow joint.
• The humerus has three main regions:
  • Proximal extremity
  • Body (shaft)
  • Distal extremity
• The main muscles and ligaments attached to the humerus are shown in Figures 3.1 and 3.5.

Proximal Extremity

• The head is the round, smooth upper end of the humerus.
• It forms about one-third of a sphere.
• It faces medially, superiorly, and slightly posteriorly.
• It articulates with the glenoid cavity of the scapula to form the glenohumeral joint.
• The greater tubercle is a large rough projection on the lateral side of the proximal humerus.
• It lies lateral to the head.
• The lesser tubercle is a small rough projection on the anterior side of the proximal humerus.
• It lies below the head and medial to the greater tubercle.
• The anatomical neck is the slightly narrowed region around the articular surface of the head.
• The articular capsule of the glenohumeral joint attaches along its lower border.
• Fractures of the anatomical neck are rare.
• They are more common in older people.
• The surgical neck is the narrowed area below the greater and lesser tubercles.
• It forms the junction between the proximal end and the shaft.
• It is closely related to the axillary nerve.
• It is also related to the anterior and posterior circumflex humeral vessels.
• Fractures of the surgical neck are common.
• The intertubercular (bicipital) groove is a deep groove on the front of the humerus.
• It lies between the greater and lesser tubercles.
• It contains the tendon of the long head of the biceps brachii muscle.
• It extends into the upper one-third of the shaft.

Body (Shaft)

• The deltoid tuberosity is a rough triangular area on the anterolateral surface of the middle of the shaft.
• The word delt- comes from the triangular Greek letter “delta.”
• It is the attachment site for the deltoid muscle.
• The posterior border of the deltoid tuberosity forms the radial nerve groove.
• The radial groove (spiral groove) is a shallow groove that winds around the back and side of the shaft.
• It is most prominent between the deltoid tuberosity and the upper end of the lateral supracondylar ridge.
• It is closely related to the radial nerve.
• It is also related to the profunda brachii vessels.
• Fractures of the middle shaft are common.
• These fractures often occur below the deltoid tuberosity.
• They may injure the radial nerve and the structures in the radial groove.
• The medial supracondylar ridge extends upward from the medial epicondyle.
• It forms the lower medial border of the humerus.
• The lateral supracondylar ridge extends upward from the lateral epicondyle.
• It forms the lower lateral border of the humerus.

Distal Extremity

• The lateral epicondyle is a small rough projection on the outer side of the distal humerus.
• It lies above the capitulum.
• It can be easily felt (palpated).
• The common extensor tendon attaches here.
• Inflammation of this tendon is called lateral epicondylitis (tennis elbow).
• The medial epicondyle is a large rounded projection on the inner side of the distal humerus.
• It lies above the trochlea.
• It is easily felt and is an important surface landmark.
• The ulnar nerve passes behind it in the ulnar sulcus.
• The ulnar nerve can be injured by trauma or fractures.
• The nerve can be felt behind the medial epicondyle.
• Striking this nerve causes the “funny bone” tingling sensation.
• The tingling is felt along the medial side of the hand and the little finger (fifth digit).
• The capitulum is a rounded articular surface on the outer side of the distal humerus.
• The word capit- is Latin for “little head.”
• It lies lateral to the trochlea.
• It articulates with the head of the radius.
• This joint allows flexion, extension, and rotation.
• The trochlea is a pulley-shaped articular surface on the inner side of the distal humerus.
• The word trochle- is Greek for “pulley.”
• It lies medial to the capitulum.
• It articulates with the trochlear notch of the ulna.
• This joint mainly allows hinge movement.
• The coronoid fossa is a depression above the trochlea on the front of the humerus.
• It receives the coronoid process of the ulna during full elbow flexion.
• The radial fossa is a shallow depression above the capitulum on the front of the humerus.
• It receives the head of the radius during full elbow flexion.
• The olecranon fossa is a deep depression above the trochlea on the back of the humerus.
• It receives the olecranon process of the ulna during elbow extension.

KEY CONCEPT

• The humerus is the longest bone of the upper limb.
• It consists of three regions: proximal extremity, shaft, and distal extremity.
• The head articulates with the glenoid cavity to form the shoulder joint.
• The surgical neck is a common fracture site and is closely related to the axillary nerve.
• The intertubercular groove contains the long head of the biceps tendon.
• The radial groove contains the radial nerve and profunda brachii vessels.
• The lateral epicondyle is the attachment site of the common extensor tendon and is affected in tennis elbow.
• The medial epicondyle is closely related to the ulnar nerve, producing the funny bone sensation when struck.
• The capitulum articulates with the radius, while the trochlea articulates with the ulna.
• The coronoid, radial, and olecranon fossae receive their corresponding bony structures during elbow movements.

Conceptual Examples

• Shoulder joint → Head of the humerus fits into the glenoid cavity like a ball in a shallow socket.
• Surgical neck fracture → May damage the axillary nerve.
• Midshaft fracture → May injure the radial nerve in the radial groove.
• Tennis elbow → Pain occurs where the common extensor tendon attaches to the lateral epicondyle.
• Hit the inside of your elbow → The ulnar nerve is stimulated behind the medial epicondyle, causing the funny bone tingling sensation.
• Bending the elbow fully → The coronoid process and head of the radius fit into the coronoid and radial fossae.
• Straightening the elbow fully → The olecranon process fits into the olecranon fossa.

Figure Numbers: Figures 3.1 and 3.5 (muscle and ligament attachments).

Clinical Notes

Proximal End of Humerus Fracture

Humeral Head Fracture

• A humeral head fracture can occur during anterior or posterior shoulder dislocation.
• The glenoid labrum may cause the fracture.
• The glenoid labrum may become trapped in the fracture defect.
• This can make reduction of the shoulder joint difficult.

Greater Tuberosity Fracture

• The greater tuberosity may fracture due to direct trauma.
• It may also be displaced by the glenoid labrum during shoulder dislocation.
• It can also be avulsed by a strong contraction of the supraspinatus muscle.
• The fractured bone fragment carries the attachments of the:
  • Supraspinatus
  • Teres minor
  • Infraspinatus
• These tendons form part of the rotator cuff.
• If associated with shoulder dislocation, the rotator cuff may tear severely.
• The greater tuberosity may remain displaced posteriorly even after the shoulder joint is reduced.
• In this situation, open reduction is needed to reattach the rotator cuff.

Lesser Tuberosity Fracture

• A lesser tuberosity fracture may occur with posterior shoulder dislocation.
• The fractured fragment receives the insertion of the subscapularis tendon.
• The subscapularis is part of the rotator cuff.

Surgical Neck Fracture

• The surgical neck lies immediately below the lesser tuberosity.
• It may fracture after a direct blow to the side of the shoulder.
• It may also fracture after falling on an outstretched hand.
• The axillary nerve lies close to the surgical neck.
• The anterior and posterior circumflex humeral vessels also lie close to it.
• These structures can be injured during a surgical neck fracture.

Shaft of Humerus Fracture

• Fractures of the shaft of the humerus are common.
• The displacement of the fragments depends on the level of the fracture compared with the deltoid muscle insertion.
• If the fracture is above the deltoid insertion:
  • The pectoralis major, latissimus dorsi, and teres major pull the proximal fragment medially (adduction).
  • The deltoid, biceps, and triceps pull the distal fragment upward (proximally).
• If the fracture is below the deltoid insertion:
  • The deltoid pulls the proximal fragment laterally (abduction).
  • The biceps and triceps pull the distal fragment upward (proximally).
• The radial nerve lies in the spiral (radial) groove on the back of the humerus.
• It may be injured in a shaft fracture.

Distal End of Humerus Fracture

• Supracondylar fractures are common in children.
• They usually occur after a fall on an outstretched hand with the elbow partly flexed.
• The median, radial, and ulnar nerves may be injured.
• Nerve function usually returns after the fracture is reduced.
• The brachial artery may be damaged or compressed.
• Swelling around the fracture can also compress the artery.
• Reduced blood flow to the forearm may lead to Volkmann’s ischemic contracture.
• The medial collateral ligament of the elbow may pull off (avulse) the medial epicondyle if the forearm is forcibly abducted.
• The ulnar nerve may be injured at the time of the fracture.
• It may also become trapped in the healing callus.
• The ulnar nerve may later be irritated by the healed irregular bone surface.

KEY CONCEPT

• Humeral head fracture → May occur during shoulder dislocation and the glenoid labrum may become trapped, making reduction difficult.
• Greater tuberosity fracture → May result from direct trauma, shoulder dislocation, or strong supraspinatus contraction.
• Lesser tuberosity fracture → Often accompanies posterior shoulder dislocation.
• Surgical neck fracture → Common injury that may damage the axillary nerve and circumflex humeral vessels.
• Shaft fracture → Fragment displacement depends on the position of the fracture relative to the deltoid insertion and may injure the radial nerve.
• Supracondylar fracture → Common in children after a fall on an outstretched hand; may injure the median, radial, ulnar nerves, or brachial artery, leading to Volkmann’s ischemic contracture.
• Medial epicondyle avulsion → May injure the ulnar nerve immediately or during healing.

Conceptual Examples

• Shoulder dislocation → Humeral head fracture → Glenoid labrum gets trapped → Shoulder is difficult to reduce.
• Strong contraction of the supraspinatus → Pulls off the greater tuberosity → Rotator cuff attachment moves with the bone fragment.
• Fall on an outstretched hand → Surgical neck fracture → Possible injury to the axillary nerve.
• Midshaft humerus fracture → Possible injury to the radial nerve in the spiral groove.
• Child falls on an outstretched hand → Supracondylar fracture → Risk of brachial artery and nerve injuries.
• Forced abduction of the forearm → Medial epicondyle avulsion → Possible ulnar nerve injury.

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