Wrist, Hand and Forearm Flashcards
How many bones are in the wrist and hand?
27 bones in total:
Phalanges: 14
Metacarpals: 5
Carpals: 8
Name the carpal bones in the proximal row.
Scaphoid
Lunate
Triquetral
Pisiform
Name the carpal bones in the distal row.
Trapezium
Trapezoid
Capitate
Hamate
What is the clinical significance of the scaphoid bone?
Commonly fractured.
Prone to avascular necrosis due to poor blood supply.
Describe the radiocarpal (wrist) joint.
Type: Synovial ellipsoid.
Movements: Flexion/extension, radial/ulnar deviation.
Close-pack position: Full extension with radial deviation
Describe the midcarpal joint.
Type: Synovial complex saddle joint.
Articulation: Between proximal and distal carpal rows.
Movements: Flexion/extension, abduction/adduction.
What are the movements at the wrist and their ranges?
Flexion: 85°
Extension: 85°
Radial Deviation: 15°
Ulnar Deviation: 45°
What is the first carpometacarpal (CMC) joint, and why is it important?
Type: Synovial saddle joint.
Articulation: Between trapezium and base of first metacarpal.
Movements: Flexion/extension, abduction/adduction, opposition.
Important for thumb mobility.
What contributes to wrist stability?
Multiple ligaments (e.g., palmar and dorsal radiocarpal, ulnocarpal).
Extensor and flexor retinacula.
Close-pack position: Extension with radial deviation.
Pronator quadratus.
Describe the metacarpophalangeal (MCP) joints.
Type: Synovial ellipsoid joints.
Movements: Flexion/extension, abduction/adduction.
Ligaments: Palmar, collateral, transverse metacarpal.
Describe the interphalangeal (IP) joints.
Type: Synovial hinge joints.
Movements: Flexion and extension.
Ligaments: Palmar and collateral.
What are the active movements of the thumb?
Flexion/Extension
Abduction/Adduction
Opposition (combination of flexion, abduction, and medial rotation).
Which muscles are involved in thumb opposition?
Flexor Pollicis Brevis (FPB)
Opponens Pollicis (OP)
Flexor Pollicis Longus (FPL)
Adductor Pollicis (AddP)
Abductor Pollicis Longus (APL)
Describe the palmar radiocarpal ligament.
Connects the radius to the proximal carpal bones.
Provides stability to the wrist during flexion and extension.
What is the clinical relevance of the TFCC (Triangular Fibrocartilaginous Complex)?
Provides stability to the distal radioulnar joint.
Often injured in wrist trauma.
What are the muscles in the superficial group of the anterior compartment of the forearm?
Pronator Teres
Flexor Carpi Radialis (FCR)
Palmaris Longus
Flexor Carpi Ulnaris (FCU)
Flexor Digitorum Superficialis (intermediate layer)
What are the muscles in the deep group of the anterior compartment of the forearm?
Flexor Digitorum Profundus (FDP)
Flexor Pollicis Longus (FPL)
Pronator Quadratus
What is the nerve supply of the anterior compartment muscles?
Median nerve: Supplies most anterior muscles.
Ulnar nerve: Supplies Flexor Carpi Ulnaris (FCU) and the medial half of Flexor Digitorum Profundus (FDP).
Describe the Pronator Teres muscle.
Origin: Medial epicondyle of humerus and coronoid process of ulna.
Insertion: Lateral surface of the mid-shaft of the radius.
Nerve supply: Median nerve (C6-C7).
Action: Pronation of the forearm.
Name the muscles in the superficial group of the posterior compartment of the forearm.
Brachioradialis
Extensor Carpi Radialis Longus (ECRL)
Extensor Carpi Radialis Brevis (ECRB)
Extensor Digitorum
Extensor Digiti Minimi (EDM)
Extensor Carpi Ulnaris (ECU)
Name the muscles in the deep group of the posterior compartment of the forearm.
Supinator
Abductor Pollicis Longus (APL)
Extensor Pollicis Longus (EPL)
Extensor Pollicis Brevis (EPB)
Extensor Indicis (EI)
What is the nerve supply of the posterior compartment muscles?
Radial nerve: Supplies Brachioradialis and Extensor Carpi Radialis Longus (ECRL).
Posterior Interosseous Nerve (branch of Radial): Supplies other posterior compartment muscles.
Describe the Extensor Digitorum (ED) muscle.
Origin: Lateral epicondyle of humerus.
Insertion: Bases of middle and distal phalanges of fingers via dorsal digital expansion.
Nerve supply: Posterior Interosseous Nerve (C7-C8).
Action: Extension of MCP and IP joints of fingers.
What muscles are responsible for wrist flexion?
Flexor Carpi Radialis (FCR)
Flexor Carpi Ulnaris (FCU)
Palmaris Longus
What muscles are responsible for wrist extension?
Extensor Carpi Radialis Longus (ECRL)
Extensor Carpi Radialis Brevis (ECRB)
Extensor Carpi Ulnaris (ECU)
What muscles produce radial deviation (abduction) of the wrist?
Flexor Carpi Radialis (FCR)
Extensor Carpi Radialis Longus (ECRL)
Extensor Carpi Radialis Brevis (ECRB)
Abductor Pollicis Longus (APL)
What muscles produce ulnar deviation (adduction) of the wrist?
Flexor Carpi Ulnaris (FCU)
Extensor Carpi Ulnaris (ECU)
Describe the Flexor Digitorum Profundus (FDP) muscle.
Origin: Medial surface of ulna and anterior interosseous membrane.
Insertion: Palmar surface of distal phalanges of fingers.
Nerve supply:
Lateral half: Median nerve (C8-T1).
Medial half: Ulnar nerve (C8-T1).
Action: Flexion of DIP, PIP, MCP, and wrist joints.
What are the borders and contents of the carpal tunnel?
Borders:
Roof: Flexor retinaculum.
Floor: Carpal bones.
Contents:
Median nerve.
Tendons of FDS, FDP, and FPL.
Synovial sheaths.
Describe the Abductor Pollicis Longus (APL) muscle.
Origin: Posterior surface of ulna, radius, and interosseous membrane.
Insertion: Base of the first metacarpal.
Nerve supply: Posterior Interosseous Nerve (C7-C8).
Action: Abduction and extension of the thumb at CMC joint.
