Anatomy of the Carpus and Hand

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Questions and Answers

Which carpal bone is most commonly fractured?

Pisiform

Scaphoid (correct)

Hamate

Trapezium

What is a major complication of a scaphoid fracture due to its blood supply?

Avascular necrosis (correct)

Bone marrow edema

Fracture nonunion

Cartilage damage

What type of fracture occurs at the first carpometacarpal joint?

Colles' fracture

Smith's fracture

Greenstick fracture

Bennet's fracture (correct)

What anatomical structure tends to pull the metacarpal shaft proximally when a Bennet's fracture occurs?

Abductor pollicis longus tendon Signup and view all the answers

Which carpal bone articulates with the base of metacarpal III?

Capitate Signup and view all the answers

Which nerve innervates the medial two lumbricals?

Ulnar nerve Signup and view all the answers

What is the primary function of the lumbricals?

Flex MCPJ and extend IPJ Signup and view all the answers

Which muscle is part of the hypothenar group?

Flexor digiti minimi Signup and view all the answers

What is the major function of the adductor pollicis?

Adduction of the thumb Signup and view all the answers

Which group of muscles is responsible for the abduction and adduction of the fingers?

Interossei Signup and view all the answers

What is one of the primary learning outcomes regarding the wrist and hand?

Revise the osteology and joints of the wrist and hand Signup and view all the answers

Which movements are specifically associated with the thumb?

Abduction, adduction, and opposition Signup and view all the answers

Which bones are part of the proximal row of the carpal bones?

Scaphoid, lunate, triquetrum, and pisiform Signup and view all the answers

What structure contains long tendons of the forearm flexors within the hand?

Carpal tunnel Signup and view all the answers

Which clinical aspect is highlighted in the learning outcomes?

Common neurovascular injuries within the hand Signup and view all the answers

Which thenar muscles are primarily responsible for thumb opposition?

Opponens pollicis Signup and view all the answers

Which layer of the palm is involved in the organization of the palmar spaces?

Deep fascia layer Signup and view all the answers

What is the orientation of thumb movements relative to digit III?

90° to the movement of digits Signup and view all the answers

Which nerve innervates the muscles of the hypothenar eminence?

Deep motor branch of the ulnar nerve Signup and view all the answers

What does the mid-palmar compartment primarily contain?

Long flexor tendons, lumbricals, and palmar arches Signup and view all the answers

What is the primary shape characteristic of the palmar aponeurosis?

Triangular Signup and view all the answers

What condition is characterized by a thickening of the palmar fascia leading to fixed positions of fingers?

Dupuytren's contracture Signup and view all the answers

Which structure is NOT found in the thenar eminence?

Lumbricals Signup and view all the answers

Which structure prevents the bowing of flexor digitorum tendons?

Synovial sheaths Signup and view all the answers

What is the function of the intrinsic muscles of the hand?

Facilitate finger abduction and adduction Signup and view all the answers

Which of the following best describes the function of the fibrous flexor tendon sheaths?

Anchor the long flexor tendons to the phalanges Signup and view all the answers

What would likely result from a damaged recurrent motor branch of the median nerve?

Loss of thumb opposition Signup and view all the answers

What is the role of the radial bursa in the hand?

Encases flexor tendons from the forearm Signup and view all the answers

Which artery mainly supplies blood to the hand?

Radial artery Signup and view all the answers

What structure does the extensor hood primarily serve as an attachment for?

Lumbricals Signup and view all the answers

Which test is used to assess arterial blood flow in the hand?

Allen's Test Signup and view all the answers

What is primarily formed by the anastomosis of the deep branch of the ulnar artery and the radial artery?

Deep palmar arch Signup and view all the answers

Which of the following arteries is NOT a contributor to the superficial palmar arch?

Radialis indicis artery Signup and view all the answers

Which band does the extensor hood NOT divide into?

Medial band Signup and view all the answers

Where does the ulnar artery enter the hand?

Between the pisiform and hook of hamate Signup and view all the answers

What is the function of the lumbricals regarding finger movement?

Flex MCP and extend IP joints Signup and view all the answers

Study Notes

Carpus and Hand

The lecture covers body movement and function of the carpus (wrist) and hand.
Learning outcomes include: revision of wrist and hand osteology and joints, muscles in the thenar and hypothenar eminences, long tendons of forearm flexors, carpal tunnel and its contents, common neurovascular injuries, clinically relevant landmarks, and intrinsic muscles/neurovascular structures.

Movements of the Hand

Abduction and adduction of fingers occur around digit III.
Movement of the thumb is at 90 degrees to the movement of the fingers.

Movements of the Thumb

Abduction, adduction, and opposition are distinct thumb movements.

Bones of the Wrist

Proximal row includes scaphoid, lunate, triquetrum, and pisiform.
Distal row includes trapezium, trapezoid, capitate, and hamate.
Key features of each bone are mentioned.

Scaphoid Fracture

The scaphoid is the most commonly fractured carpal bone.
Fractures typically occur across the "waist" of the bone.
Blood supply to the scaphoid is distal to proximal, which can lead to risk of avascular necrosis.

Bennett's Fracture

This is a fracture of the first carpometacarpal joint (CMC joint) of the thumb.
The synovial joint is saddle-shaped.
The abductor pollicis longus tendon plays a role in stabilizing and abducting the thumb.

Hypothenar and Thenar Eminences

Hypothenar eminence contains three muscles of the little finger, innervated by the deep branch of the ulnar nerve.
Thenar eminence contains muscles of the thumb, innervated by the recurrent branch of the median nerve.

Compartments of the Hand

Midpalmar compartment contains long flexor tendons, lumbricals, and palmar arches.
Hypothenar eminence contains three little finger muscles.
Thenar eminence contains muscles for the thumb.

Synovial Sheaths

Fibrous sheaths (e.g., FDP and FDS) hold tendons to phalanges, preventing bowing.
FPL tendon sheath is also noted.

Fascia of the Hand

Includes palmar aponeurosis (a condensation of deep fascia), palmar carpal ligament, and flexor retinaculum.
Flexor retinaculum (transverse carpal ligament) is mentioned.
Structures described are palmar aponeurosis, palmar carpal ligament, and flexor retinaculum

Palmar Aponeurosis

A triangular-shaped condensation of deep palmar fascia.
Anchored to flexor retinaculum, divides into slips for insertions; fibrous flexor tendon sheaths and deep transverse ligaments.

Dupuytren's Contracture

A benign fibroproliferative disorder of the palmar fascia.
Fascia thickens, causing fingers to flex and become fixed.
Often affects the fourth and fifth digits.
Surgery may be required to relieve symptoms.

Intrinsic Muscles of the Hand

Hypothenar group, thenar group, and lumbricals are intrinsic muscles innervated by various nerve branches.

Lumbricals

Arise from the FDP tendon.
Insert into the radial side of the MP joints and extensor hood.
Lateral lumbricals receive innervation from the median nerve; medial lumbricals from the ulnar nerve.

Dorsal and Palmar Interossei

Dorsal interossei abduct fingers.
Palmar interossei adduct fingers.
Both are innervated by the deep branch of the ulnar nerve.

Extensor Hood

Tendons of extensor digitorum and extensor pollicis longus expand over the proximal phalanx.
Serves as an attachment for lumbricals, dorsal interossei, and palmar interossei, and for flexing MCP and extending IP.

Blood Supply

Ulnar artery and radial artery supply blood to the hand.
Ulnar artery is anterior to the flexor retinaculum between the pisiform and hook of the hamate.
Radial artery curves around scaphoid/trapezium and anastomoses with deep branch of the ulnar artery.

Allen's Test

Used to assess collateral circulation of the radial and ulnar arteries.
The radial artery is most commonly used for testing access.

Surface Anatomy

Superficial arch is at the level of the tip of the thumb.
Deep arch is at the base of the extended thumb.

Carpal Tunnel Syndrome

Any lesion (e.g. inflammation, infection, fluid retention, or arthritis) causing compression of the median nerve in the carpal tunnel can cause symptoms.
Symptoms include median nerve compression, paraesthesia, and loss of function in the hand.
Clinical presentation, diagnostic work up, and treatment are not included.

Cutaneous Innervation

Various nerves (e.g., axillary, radial, musculocutaneous, and median) provide sensation to different regions of the arm/hand.

Dermatomes

Dermatomes are mapped skin regions, and their related segments of the spinal cord and peripheral nerves.

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Description

This quiz focuses on the anatomy and movements of the carpus and hand. Students will explore the osteology of the wrist, muscle groups, and common neurovascular injuries related to hand function. It is essential for understanding clinical applications and anatomical landmarks.