Upper and Lower Limb Anatomy and Clinical Correlations

Comprehensive practice flashcards covering upper and lower limb osteology, joints, muscular anatomy, compartments, neurovascular pathways, the brachial plexus, and associated clinical nerve lesions.

What are the four anatomical regions of the upper limb and their boundaries?

1. Shoulder region: Transitional between the trunk and free limb; 2. Arm: Proximal segment between the glenohumeral and elbow joints; 3. Forearm: Second segment between the elbow and wrist joints; 4. Hand: Distal segment composed of the wrist, palm, dorsum of hand, and digits.

What are the three major transition spaces through which neurovascular structures travel between regions of the upper limb?

1. Axilla (anterior to glenohumeral joint; connects neck/trunk to arm); 2. Cubital Fossa (anterior to elbow; connects arm to forearm); 3. Carpal Tunnel (anterior to wrist; connects forearm to hand).

What are the four anatomical regions of the lower limb and their boundaries?

1. Gluteal region: Transitional area located posteriorly between the iliac crest and gluteal fold; 2. Thigh: Proximal segment between the hip and knee joints; 3. Leg: Second segment between the knee and talocrural (ankle) joints; 4. Foot: Distal segment composed of the ankle, sole, dorsum of foot, and digits.

What three major transition spaces for lower limb neurovascular structures are highlighted in this diagram?

The femoral triangle (anterior to hip joint), popliteal fossa (posterior to knee), and tarsal tunnel (posteromedial to talocrural joint).

What bone and labeled anatomical features are shown in these superior and inferior views?

The clavicle, showing the sternal end, acromial end, shaft, conoid tubercle, trapezoid line, subclavian groove, impression for costoclavicular ligament, and articular facets.

What muscles attach to the greater tubercle and lesser tubercle of the humerus?

The greater tubercle provides attachment for the supraspinatus (superior facet), infraspinatus (middle facet), and teres minor (inferior facet). The lesser tubercle provides attachment for the subscapularis.

What muscular attachments are found on the lips and floor of the intertubercular (bicipital) sulcus of the humerus?

The lateral lip receives the pectoralis major; the floor receives the latissimus dorsi; the medial lip receives the teres major.

What type of joint is the sternoclavicular joint, and what surfaces articulate to form it?

It is a synovial saddle-shaped joint formed by the manubrium of the sternum, the first costal cartilage, and the sternal end of the clavicle. It provides the only bony articulation between the upper limb and the axial skeleton.

Which extrinsic ligaments compose the coracoclavicular ligament that reinforces the acromioclavicular joint?

The conoid ligament and the trapezoid ligament.

What structures form the coracoacromial arch, and what is its functional importance?

It is formed by the acromion, the coracoid process, and the coracoacromial ligament. It prevents upward displacement of the head of the humerus within the glenohumeral joint.

What are the articulations and stabilizing ligaments of the elbow joint?

A synovial hinge joint composed of: 1) trochlea of humerus articulating with trochlear notch of ulna; 2) capitulum of humerus articulating with superior radial head. It is reinforced by the radial collateral ligament (limits adduction) and ulnar collateral ligament (limits abduction).

What type of joint is the proximal radioulnar joint, and what ligament primarily stabilizes it?

A synovial pivot joint formed between the head of the radius and the radial notch of the ulna, primarily stabilized by the annular ligament.

What is the anatomical mechanism of nursemaid's elbow (subluxation of the radial head)?

A sudden pull on the upper limb tears the annular ligament, displacing the radial head inferiorly and often trapping the superior portion of the annular ligament between the capitulum and radial head.

What bones form the proximal and distal rows of carpal bones from lateral to medial?

Proximal row: Scaphoid, Lunate, Triquetrum, Pisiform. Distal row: Trapezium, Trapezoid, Capitate, Hamate.

What surfaces articulate at the radiocarpal (wrist) joint, and what type of joint is it?

A condyloid synovial joint where the distal end of the radius articulates with the proximal surfaces of the scaphoid and lunate bones (with the triquetrum articulating during wrist adduction).

What is the origin, insertion, innervation, and action of the serratus anterior muscle?

Origin: Ribs 1–8; Insertion: Anterior surface of the vertebral border of the scapula; Innervation: Long thoracic nerve ($C5, C6, C7$); Actions: Protracts and rotates the scapula, holding it against the thoracic wall.

What are the four rotator cuff muscles (SITS) and their primary actions at the glenohumeral joint?

Supraspinatus (initiates abduction up to $15^\circ$), Infraspinatus (lateral rotation), Teres minor (lateral rotation and weak adduction), and Subscapularis (medial rotation and adduction). Together, they form a musculotendinous collar that stabilizes the joint.

What are the origins, insertion, actions, and innervation of the biceps brachii muscle?

Origin: Long head from supraglenoid tubercle, short head from coracoid process; Insertion: Radial tuberosity; Actions: Supinates and flexes forearm, assists shoulder flexion; Innervation: Musculocutaneous nerve.

Which anterior forearm muscle is the sole muscle capable of flexing the distal interphalangeal (DIP) joints of the medial four digits?

Flexor digitorum profundus (FDP).

What anatomical surface region, boundaries, and contents are illustrated here?

The anatomical snuffbox. Boundaries: tendons of abductor pollicis longus and extensor pollicis brevis (anterior), tendon of extensor pollicis longus (posterior); Floor: scaphoid and trapezium; Contents: radial artery and cephalic vein.

What anatomical space and its contained tendons and nerve are shown in this cross section of the wrist?

The carpal tunnel, containing 4 tendons of flexor digitorum profundus, 4 tendons of flexor digitorum superficialis, 1 tendon of flexor pollicis longus, and the median nerve beneath the flexor retinaculum.

What are the boundaries of the carpal arch forming the base of the carpal tunnel?

Medial base: Pisiform and hook of hamate; Lateral base: Tubercles of the scaphoid and trapezium.

What are the three muscles of the thenar compartment, their innervation, and their actions?

Abductor pollicis brevis (abducts thumb), Flexor pollicis brevis (flexes thumb at MCP joint), and Opponens pollicis (opposes thumb by medial rotation); all are innervated by the recurrent branch of the median nerve.

What are the muscle actions and innervations of the palmar versus dorsal interossei?

Palmar interossei adduct digits 2, 4, and 5 (PAD); Dorsal interossei abduct digits 2, 3, and 4 (DAB). Both groups are innervated by the ulnar nerve.

What biomechanical structure and combined digit action are demonstrated in this illustration?

The extensor hood mechanism: intrinsic hand muscles (lumbricals and interossei) pass ventral to the MCP joint to flex it, while inserting into lateral bands dorsal to the IP joints to extend the PIP and DIP joints.

What is the dual innervation pattern of the four lumbrical muscles?

The 1st and 2nd lumbricals are innervated by the median nerve; the 3rd and 4th lumbricals are innervated by the ulnar nerve.

What are the anatomical boundaries of the axilla?

Apex: Cervicoaxillary canal; Anterior wall: Pectoralis major and minor; Posterior wall: Subscapularis, teres major, and latissimus dorsi; Medial wall: Serratus anterior on thoracic wall; Lateral wall: Intertubercular groove of humerus; Base: Skin and axillary fascia.

What branches arise from the three parts of the axillary artery?

First part (1 branch): Superior thoracic artery; Second part (2 branches): Thoraco-acromial artery and lateral thoracic artery; Third part (3 branches): Subscapular artery, anterior circumflex humeral artery, and posterior circumflex humeral artery.

What are the primary arterial contributors to the superficial and deep palmar arterial arches?

The superficial palmar arterial arch receives blood primarily from the ulnar artery (anastomosing with the superficial palmar branch of the radial artery); the deep palmar arterial arch receives blood primarily from the radial artery (anastomosing with the deep palmar branch of the ulnar artery).

What superficial vein connects the cephalic and basilic veins across the cubital fossa and serves as a common venipuncture site?

The median cubital vein.

How are the roots, trunks, divisions, and cords of the brachial plexus structured?

5 Roots ($C5-T1$ anterior rami) form 3 Trunks: Superior ($C5-C6$), Middle ($C7$), and Inferior ($C8-T1$). Each trunk forms an anterior and posterior division. All posterior divisions unite to form the Posterior cord. Anterior divisions of superior and middle trunks form the Lateral cord, while the anterior division of the inferior trunk continues as the Medial cord.

What are the specific sensory testing locations for spinal cord segments C5 through T1?

$C5$: upper/lateral arm; $C6$: pollex (thumb); $C7$: 3rd digit; $C8$: 5th digit (pinky); $T1$: medial aspect of elbow.

What clinical deformity results from an injury to the radial nerve in the radial groove of the humerus?

Wrist drop, caused by paralysis of the wrist and finger extensor muscles in the posterior compartment of the forearm.

What hand presentation is shown here, characterized by thenar wasting and an inability to oppose the thumb?

Ape hand deformity, resulting from a low median nerve injury (such as severe carpal tunnel syndrome).

What clinical sign is shown here when a patient attempts to make a fist following a high median nerve injury?

Hand of benediction (inability to flex digits 1, 2, and 3 due to paralysis of FDS, lateral half of FDP, and FPL).

What cutaneous sensory distribution to the dorsal surface of the hand is represented by the areas labeled U, R, and M?

U: Ulnar nerve (medial $1\frac{1}{2}$ digits and medial dorsum); R: Superficial radial nerve (lateral dorsum of hand and proximal digits); M: Median nerve (dorsal tips/distal segments of the lateral $3\frac{1}{2}$ digits).