Questions and Answers
Which compartment of the hand primarily contains muscles involved in thumb opposition?
What differentiates intrinsic muscles from extrinsic muscles in the hand?
Which of the following structures is NOT located in the palmar aspect of the hand?
Which of the following describes the relationship between extrinsic muscles and tendons in the hand?
Signup and view all the answers
Which muscle group is majorly responsible for movement within the central compartment of the hand?
Signup and view all the answers
Which muscle is responsible for pulling the thumb medially and forward?
Signup and view all the answers
What is the origin of the adductor pollicis?
Signup and view all the answers
What is the primary cause of tenosynovitis of flexor tendons?
Signup and view all the answers
Which statement accurately describes the lumbrical muscles?
Signup and view all the answers
Which nerve supplies the abductor digiti minimi?
Signup and view all the answers
What is the primary function of the palmaris brevis?
Signup and view all the answers
Which muscle action primarily involves abducting the little finger?
Signup and view all the answers
Which tendon arrangement results in the 'buttonhole effect'?
Signup and view all the answers
Which structure acts as a strong fibrous sheath attached to the sides of the phalanges?
Signup and view all the answers
What action does the opponens digiti minimi perform?
Signup and view all the answers
How many interosseous muscles are present in the hand?
Signup and view all the answers
Which nerve roots primarily supply the muscles of the little finger?
Signup and view all the answers
What occurs if the pressure within a tenosynovial sheath rises significantly?
Signup and view all the answers
Which of the following statements about the interosseous muscles is incorrect?
Signup and view all the answers
In the thumb, what does the osseofibrous tunnel contain?
Signup and view all the answers
Which structure does the tendon of the flexor digitorum profundus pass through?
Signup and view all the answers
What is the effect of tenosynovitis on finger movement?
Signup and view all the answers
What is the function of the interosseous muscles during finger movements?
Signup and view all the answers
Which muscle does NOT belong to the hypothenar compartment?
Signup and view all the answers
What is the primary action of the dorsal interossei?
Signup and view all the answers
Which nerve supplies the adductor pollicis muscle?
Signup and view all the answers
What is the action of the palmaris brevis muscle?
Signup and view all the answers
Which intrinsic hand muscle is responsible for flexing the metacarpophalangeal joints and extending the interphalangeal joints of the fingers except the thumb?
Signup and view all the answers
Which of the following muscles is NOT innervated by the ulnar nerve?
Signup and view all the answers
Which muscle's origin is from the anterior surface of the shafts of metacarpal bones?
Signup and view all the answers
What specific function does the opponens pollicis serve?
Signup and view all the answers
What is the main consequence of delayed diagnosis in forearm compartment syndrome?
Signup and view all the answers
Which muscles are primarily affected in Volkmann's ischemic contracture?
Signup and view all the answers
What is a common cause of tennis elbow?
Signup and view all the answers
What condition arises from edema and fibrosis of the synovial sheath of the abductor pollicis longus and extensor pollicis brevis tendons?
Signup and view all the answers
What is the typical result of a rupture of the extensor pollicis longus tendon?
Signup and view all the answers
Which sign is NOT an early indicator of forearm compartment syndrome?
Signup and view all the answers
What is the main action of the biceps brachii muscle?
Signup and view all the answers
Which nerve supplies the brachialis muscle?
Signup and view all the answers
What anatomical structure is commonly associated with the absence of the palmaris longus?
Signup and view all the answers
Which muscle's action includes both flexion and adduction at the wrist joint?
Signup and view all the answers
What is the origin of the long head of the triceps muscle?
Signup and view all the answers
Which type of deformity occurs when both flexor and extensor muscles are contracted historically?
Signup and view all the answers
What is the primary action performed by the Pronator Teres?
Signup and view all the answers
What leads to localized ischemic necrosis in Volkmann's ischemic contracture?
Signup and view all the answers
Which muscle group mainly produces flexion or pronation in the forearm?
Signup and view all the answers
Which nerve supplies both the Flexor Carpi Radialis and the Palmaris Longus?
Signup and view all the answers
Which of the following muscles is considered part of the superficial group of the anterior compartment?
Signup and view all the answers
What characteristic symptom is associated with tennis elbow?
Signup and view all the answers
Which muscle can flex the distal phalanx of the thumb?
Signup and view all the answers
What is the primary action of the lateral head of the triceps muscle?
Signup and view all the answers
Which muscle is primarily responsible for flexing the middle phalanx of the medial four fingers?
Signup and view all the answers
Which nerve is responsible for innervating the muscles in the lateral compartment of the forearm?
Signup and view all the answers
What is a common origin for the muscles in the superficial group of the anterior compartment?
Signup and view all the answers
Which muscle originates from the medial epicondyle of the humerus and the medial border of the coronoid process of the ulna?
Signup and view all the answers
Which muscle is innervated by the anterior interosseous branch of the median nerve?
Signup and view all the answers
Which pair of muscles acts to flex the distal phalanx of the fingers?
Signup and view all the answers
Which muscle primarily acts to flex the forearm at the elbow joint?
Signup and view all the answers
Which nerve supplies the extensor pollicis longus muscle?
Signup and view all the answers
What is the primary action of the extensor carpi ulnaris?
Signup and view all the answers
Which muscle's origin is from the lateral supracondylar ridge of the humerus?
Signup and view all the answers
What is the predominant nerve root supply for the extensor carpi radialis longus?
Signup and view all the answers
Which structure is responsible for extending the metacarpophalangeal joint of the little finger?
Signup and view all the answers
What is the action of the supinator muscle?
Signup and view all the answers
Which muscle primarily assists in abduction and extension of the thumb?
Signup and view all the answers
What is the primary function of the synovial flexor sheaths in the hand?
Signup and view all the answers
Which statement correctly describes the relationship between the flexor pollicis longus tendon and the common synovial sheath?
Signup and view all the answers
What anatomical structure contains the tendon of the flexor pollicis longus?
Signup and view all the answers
How do the fibrous and synovial sheath structures differ?
Signup and view all the answers
What role do the vincula longa and brevia serve in relation to the tendons?
Signup and view all the answers
Which tendons invaginate a common synovial sheath from the lateral side?
Signup and view all the answers
Where does the lateral part of the common synovial sheath stop?
Signup and view all the answers
In which location are the fibrous sheaths the thickest?
Signup and view all the answers
Which structure lies between the thenar and midpalmar spaces?
Signup and view all the answers
What is a potential consequence of infection in the fascial spaces of the palm?
Signup and view all the answers
Which muscle is found in the thenar space?
Signup and view all the answers
How is the blood supply to the terminal phalanx structured?
Signup and view all the answers
What role does the palmar aponeurosis play in the palm?
Signup and view all the answers
Which structural feature helps prevent infection spread in the fingers?
Signup and view all the answers
What primarily occupies each pulp space in the fingers?
Signup and view all the answers
What structure is closed off from the forearm by the walls of the carpal tunnel?
Signup and view all the answers
Study Notes
Osseofascial Compartments of the Hand
- The hand contains both extrinsic muscles (originating from the forearm) and intrinsic muscles (originating and inserting within the hand).
- Organized into five compartments: thenar, hypothenar, central (midpalmar), interosseous (palmar and dorsal), and extensor (dorsal aspect).
- Thenar compartment includes muscles related to thumb movement; hypothenar is responsible for little finger mobility.
Tenosynovitis
- Tenosynovitis arises from bacterial infection in synovial sheaths, typically via penetrating wounds.
- Symptoms include finger swelling, pain on extension, and semi-flexed positions due to pus distention.
- If untreated, increased pressure might lead to tendon ischemia and potential rupture.
Flexor Tendon Anatomy
- Flexor digitorum superficialis splits into two halves around tendeons of the flexor digitorum profundus, creating the "buttonhole effect."
- Each superficialis tendon re-divides into slips toward the middle phalanx, while the profundus tendon attaches to the distal phalanx.
Palmaris Brevis Muscle
- Palmaris brevis originates from the flexor retinaculum, improving grip by corrugating skin at hypothenar.
- Innervation via the superficial branch of the ulnar nerve.
Lumbrical Muscles
- Four lumbricals arise from flexor digitorum profundus tendons, inserting into digits 2-5.
- They flex metacarpophalangeal joints while extending interphalangeal joints, identified by position (medial to lateral).
Interosseous Muscles
- Composed of eight muscles: four palmar (adduct fingers towards the third digit) and four dorsal (abduct fingers away).
- Innervated by the deep branch of the ulnar nerve.
Synovial Flexor Sheaths
- Flexor tendons of the hand are sheathed in synovial membranes, allowing smooth movement.
- Sheath continuity differs between digits; the little finger has uninterrupted sheath, while the index, middle, and ring fingers acquire individual sheaths.
Fibrous Flexor Sheaths
- Each finger has a fibrous sheath that attaches to phalanges, facilitating tendon movement and stability.
- The sheath's thick over phalanges and closes around the distal phalanx.
Clinical Considerations
- Early detection of compartment syndrome in the forearm is crucial due to secondary blood vessel compression.
- Symptoms include altered sensation, disproportionate pain, and tenderness. Delay in intervention can lead to irreversible muscle damage.
- Volkmann's contracture may follow forearm fractures, causing deformities based on muscle group contractions.
Muscle Tables
- Intrinsic Muscles of the Hand: Includes the palmaris brevis, lumbricals, and interossei, each with a specific origin, insertion, innervation, and function.
- Short Muscles of the Thumb: Abductor pollicis brevis, flexor pollicis brevis support thumb mobilization and are innervated primarily by the median and ulnar nerves.
- Muscles of the Anterior Forearm: Comprised of various flexor muscles, innervated by the median and ulnar nerves, facilitating flexion and pronation at wrist and elbow.
Summary of Forearm Muscles
- Organized into anterior, lateral, and posterior compartments impacting elbow and wrist functions.
- Anterior compartment predominantly flexes and pronates, while lateral and posterior principally extend and supinate.
- Comprised of key muscles including biceps brachii, triceps, and various flexors relating to wrist and digit movement.### Anterior Osseofascial Compartment Muscles
- Muscles are categorized into superficial, intermediate, and deep groups.
- Superficial group: Includes flexor carpi ulnaris, palmaris longus, flexor carpi radialis, and pronator teres, all sharing a common tendon of origin from the medial epicondyle of the humerus.
- Intermediate group: Comprises the flexor digitorum superficialis.
- Deep group: Features flexor digitorum profundus, flexor pollicis longus, and pronator quadratus.
Lateral Osseofascial Compartment Muscles
- Contains two main muscles: brachioradialis and extensor carpi radialis longus.
- Some classifications consider this group as part of the posterior compartment.
-
Brachioradialis:
- Origin: Lateral supracondylar ridge of humerus
- Insertion: Base of styloid process of radius
- Action: Flexes the forearm and rotates to midprone position.
-
Extensor carpi radialis longus:
- Origin: Lateral supracondylar ridge of humerus
- Insertion: Base of second metacarpal
- Action: Extends and abducts the hand at the wrist.
Posterior Forearm Osseofascial Compartment Muscles
- Extensor carpi radialis brevis: Extends and abducts the hand; originates from the lateral epicondyle.
- Extensor digitorum: Extends fingers and hand; affects the medial four fingers.
- Extensor digiti minimi: Specifically extends the little finger.
- Extensor carpi ulnaris: Extends and adducts the hand; inserts at the base of the fifth metacarpal.
- Anconeus: Extends the elbow joint; extends from lateral epicondyle to ulna.
- Supinator: Supinates the forearm; works with the deep branch of the radial nerve.
- Abductor pollicis longus: Abducts and extends the thumb.
- Extensor pollicis brevis: Extends the thumb at the metacarpophalangeal joint.
- Extensor pollicis longus: Extends the distal phalanx of the thumb.
- Extensor indicis: Extends the index finger.
Clinical Notes on Compartment Syndrome
- Compartment syndrome occurs due to edema causing compression within tight forearm compartments.
- Initially affects vein compression, followed by arterial compression.
- Commonly caused by soft tissue injury; early detection is vital.
Fascial Spaces of the Palm and Infection
- The fascial spaces are significant as they can become infected, leading to conditions such as acute suppurative tenosynovitis.
- Infections may arise from penetrating injuries, such as dirty nails.
- Finger pulp spaces: Each pulp space is enclosed; subdivided by septa passing from deep fascia to the periosteum.
Palmar and Pulp Fascial Spaces
- The wrist and palm have thickened deep fascia forming structures like the flexor retinaculum and palmar aponeurosis.
- Palmar aponeurosis: A triangular structure dividing the palm into the thenar and midpalmar spaces.
- The thenar space contains the first lumbrical muscle, while the midpalmar space hosts the second, third, and fourth lumbrical muscles.
- Lumbrical canals surround each lumbrical muscle tendon, normally filled with connective tissue and continuous with palmar spaces.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the anatomy of the hand, particularly focusing on the muscles involved in thumb opposition and the differences between intrinsic and extrinsic muscles. This quiz covers the structures located in the palmar aspect of the hand and the relationship between muscle groups and their tendons.