Hand, Carpus 1 Flashcards
What are the 3 types of bones in the hand?
- Carpals
- Metacarpals
- Phalanges
What are the Carpal Bones?
- Scaphoid
- Lunate
- Triquetrum
- Pisiform
- Trapezium
- Trapezoid
- Capitate
- Hamate
Which of the Carpal Bones are in the Proximal Row?
- Scaphoid
- Lunate
- Triquetrum
- Pisiform
Which of the Carpal Bones are in the Distal Row?
- Trapezium
- Trapezoid
- Capitate
- Hamate
What type of bone is the Pisiform?
Sesamoid Bone
Which of the Carpal Bones does the Radius articulate with?
Scaphoid and Lunate
Which of the Carpal Bones does the Ulna articulate with?
None, but forms an articulating surface with the Triquetrum
What are the parts of a Metacarpal bone?
- Head
- Shaft
- Base
What does the head of the Metacarpal articulate with?
The Proximal Phalynx–> forms the knuckle
What does the base of the Metacarpals articulate with?
The Carpal Bones
What are the parts of a Phalange bone?
For digits 2-5–> Distal, Middle and Proximal
For 1st digit (thumb)–> Distal and Proximal
Describe the 1st Carpometacarpal Joint
It is a saddle-type synovial joint–> gives the thumb a wide range of movements (Flexion, Extension, Abduction and Adduction)
What happens if the 1st Carpometacarpal Joint is Fractured?
Known as Bennet’s Fracture–> Caused by Hyperabduction of the thumb and results in no grip in the thumb
Describe Abduction in the fingers
Movement of the fingers away from the midline of the hand
Describe Adduction in the fingers
Movement of the fingers towards the midline of the hand
What nerve is responsible for Abduction and Adduction in the fingers?
Ulnar Nerve
What are the Intrinsic Muscles of the Hand?
- Thenar Muscles
- Hypothenar Muscles
- Lumbricals
- Interossei Muscles
- Palmaris Brevis
- Adductor Pollicis
What are the Thenar Muscles?
- Abductor Pollicis Brevis (APB)
- Flexor Pollicis Brevis (FPB)
- Opponens Pollicis (OP)
- Adductor Pollicis
What is the origin of Abductor Pollicis Brevis (APB)?
Lateral Carpal Bones
Where does the Abductor Pollicis Brevis (APB) Attach?
Proximal Phalanx of thumb
What is the nerve supply of Abductor Pollicis Brevis APB)?
Median Nerve
What is the function of Abductor Pollicis Brevis (APB)?
Abduction of the Thumb
What is the origin of Flexor Pollicis Brevis (FPB)?
Lateral Carpal Bones
Where does Flexor Pollicis Brevis (FPB) attach?
Proximal Phalanx of Thumb
What is the nerve supply of Flexor Pollicis Brevis (FPB)?
Median Nerve
What is the function of Flexor Pollicis Brevis (FPB)?
Flexion of the Metacarpophalangeal Joint of Thumb
What is the origin of Opponens Pollicis (OP)
Lateral Carpal Bones
Where does Opponens Pollicis (OP) attach?
The Lateral Border of the 1st Metacarpal
What is the nerve supply of Opponens Pollicis (OP)?
Median Nerve
What is the function of Opponens Pollicis (OP)?
Opposition of the Thumb
What is the origin of Adductor Pollicis?
Capitate, 2nd and 3rd Metacarpals
Where does Adductor Pollicis attach?
Proximal 1st Phalanx
What is the nerve supply of Adductor Pollicis?
Ulnar Nerve
What is the function of Adductor Pollicis?
Adduction of the Thumb
What are the Hypothenar Muscles?
- Abductor Digiti Minimi
- Flexor Digiti Minimi
- Opponens Digiti Minimi
What is the nerve supply of the Hypothenar Muscles?
Ulnar Nerve
What are Lumbrical Muscles?
Muscles that arise from the tendons of Flexor Digitorum Profundus–> They pass on the radial side of the metacarpophalangeal join to join extensor expansions
What are the functions of the Lumbrical Muscles?
- Flexion of the Metacarpophalangeal Joint
- Extension of the Interphalangeal Joints
- -> Overall movement: Straight finger flexion
What is the nerve supply of the Lumbrical Muscles?
1/2 Median Nerve, 1/2 Ulnar Nerve
What are the 2 groups of Interossei Muscles?
- Palmar Interossei Muscles
2. Dorsal Interossei Muscles
What is the function of Palmar Interossei Muscles?
Palmar Interossei Muscles ADducts the fingers (PAD)
What is the function of Dorsal Interossei Muscles?
Dorsal Interossei Muscles ABducts the fingers (DAB)
What is the nerve supply of Interossei Muscles?
Ulnar Nerve
Describe the Nervous Supply of the Intrinsic Muscles of the Hand
All the Intrinsic Muscles of the Hand are supplied by the Ulnar Nerve with the exception of 1/2 of the Lumbricals, Opponens Pollicis, Abductor Pollicis Brevis and Flexor Pollicis Brevis which are all supplied by the Median Nerve
What are Palmar Spaces?
Spaces between the Long Flexors and Interossei/Adductor Pollicis
What is the Palmar Aponeurosis?
The fascia overlying the palm of the hand
What is the function of the Palmar Aponeurosis?
To maintain the structural integrity of the hand during flexion
What are the borders of the Carpal Tunnel?
- Carpal Arch
2. Flexor Retinaculum
What forms the Carpal Arch?
- Scaphoid
- Trapezium
- Trapezoid
- Capitate
- Hamate
- Triquetrum
- Pisiform
What passes through the Carpal Tunnel?
- 4 tendons of Flexor Digitorum Superficialis
- 4 tendons of Flexor Digitorum Profundus
- Flexor Pollicis Longus
- Median Nerve
What happens if there is swelling/inflammation near the carpal tunnel?
There can be Carpal Tunnel Syndrome–> Compression of the Median Nerve, causing Motor Loss of the Thenar Muscles
What is the main concern if the patient has a Scaphoid Fracture?
Avascular Necrosis of the proximal part
How do you check if a patient has Carpal Tunnel Syndrome?
- Check the Thenar Muscles for Motor Function
- Test the Sensory Function of the skin of the palm–> if it works, then the patient has Carpal tunnel Syndrome. If it does not work, the patient has a lesion in the Median Nerve prior to the Carpal Tunnel
How do you check for Scaphoid Fracture?
- Press on the anatomical snuffbox of both hands of the patient
- If it hurts and stays sore on 1 side compared to the other, there is a fracture there
What is caused by fibrosis in the Palmar Aponeurosis?
Dupuytren’s Contraction–> results in shortening and thickening the the digital bands that pulls the 4th and 5th digits to varying degrees of flexion
