Forearm Flexor Aspect Flashcards
What is the only intrinsic movement of forearm? and what muscles are used to do this movement?
Rotatory
the radius is moved in an arc medially around the ulna in pronation and laterally in supination, with the proximal (upper) and distal (lower) radio-ulnar joints acting as pivots and the interosseous membrane as a hinge.
interosseous membrane attaches what together and how
The interosseous membrane is attached to the medial border of the radius and the lateral border of the ulna and, together with medial and lateral intermuscular septa, separate the anterior (or flexor) compartment from the posterior (or extensor) compartment in the forearm. These compartments are not symmetrically arranged in front of and behind the bones until the distal end of the forearm.
What 8 carpal bones make up the wrist
Forms how many rows?
2 rows:
scaphoid, lunate, triquetral and pisiform
proximally; trapezium, trapezoid, capitate and hamate distally
3 joints of the wrist
1 the wrist joint proper (radio-carpal) between the radius and the fibrous articular disc (also known as
the triangular ligament) proximally, and the scaphoid, lunate and triquetral distally (the ulna is excluded from the wrist joint by the articular disc, but articulates with the lower end of the radius at the distal radio-ulnar joint)
2 the mid-carpal or transverse intercarpal joint between the two rows of carpal bones
3 the carpo-metacarpal joint between the distal row of carpals and the medial 4 digits.
Define Supination and pronation in terms of bone position
- what muscles allow pronation and what ones allow supination
Sup: Bones parallel
pronation -> distal end of radius rolls up over top of the ulna I just rotates at humeral-radial joint
pronator teres and pronator quadratus muscles in the forearm allow pronation
supinator and biceps brachii muscles allow supination
Proximal vs distal end difference
Prox end: Forearm compartments still lateral
Distal: Forearm compartments now anterior and posterior and tendons down by wrist, no muscle bellies
Where is the Sacciform recess, Fibrious articlaur disc, Wrist joint proper
lecture slide
Inferior (distal) radio-ulnar joint: Where is it?
Lecture Slide
Head of ulna and ulna notch
What is the only sexually
dymorphic features in forearmbones
Carrying angle:
Males less 15 degrees, females greater 15 degrees as it gives them more clearance due to wider hips
Functions of the Interosseous membrane
- Hinge
- Muscle attachment
- Force transmission
-allows bones to change position we each other but not drift too far apart - also gives more attachment sites for your forearm muscles
Where is anular ligament (insertion and origin), fibruous articular disc, oblique cord
Lecture Slide
Anular ligament:
o= radial notch on ulna
i= radial head of radius
Interosseous membrane characteristics
investing fascia between the bones
Strong, fibrous collagenous sheet
Links lateral edge of ULNA to medial border of RADIUS
Movement options at each joint
flexion/extension, abduction/adduction and some rotation at the wrist
some flexion/extension at the mid-carpal joint
very little movement at the carpo-metacarpal joint
Carpal Tunnel is made up of
The flexor retinaculum spans the medial half to two thirds of the wrist (i.e. it doesn’t extend near the radial edge of the wrist). It is attached to the pisiform and hook of the hamate medially, and the tubercles of the scaphoid and trapezium laterally.
Within this carpal tunnel the common synovial sheath houses the long flexor tendons, and the sometimes a separate synovial sheath for the long flexor of the thumb can be found.
Label the hand
How many carpals, metacarpals, digits
Lecture Slide
carpals: 8
metacarpals: 5
digits: 5 (thumb is #1)
What/where are the joints in the carpal and movements at each joint
1 = Radiocarpal joint: Radius, scaphoid, triquetral and lunate
(almost all wrist movement comes from this joint, flexion/extension
abduction/adduction)
2 = Midcarpal joint (slight flexion and extension)
3 = Carpometacarpal joint (almost immobile except for saddle joint at thumb with trapezium giving flexion/extension, abduction/adduction, little bit of rotation)
What are the rows of the carpal?
Row 1 lateral -> medial: Scaphoid, lunate, triquetral, pisiform
Row 2 lateral -> medial: Trapezium, Trapezoid, capitate, hamate
Extensor retinaculum and Flexor retinaculum (Deep fascia)
- What are they
- Role
Extensor retinaculum
same as flexor retinaculum but helps hold tendons on posterior side of wrist. Very inflexible
Flexor retinaculum (Deep fascia)
strap that connects outer carpal bones to stop tendons bowstringing. Connect Scaphoid to pisiform in first row and then trapezium to hamate in second row.
retinaculum act a bit like Pulleys to give muscles
a mechanical advantage so they can do their action more efficiently (deep hold tendons in place)
compartment syndrome
bones a relatively inflexible retinaculum create carpal tunnel that most of your tendons will run thorugh, any swelling etc there
compartment syndrome , median nerve can be
compressed by inflammation, blood etc and can be overused also compress arterial blood supply
he bulky muscles of the flexor compartment fall into 3 groups:
superficial, intermediate and deep
What are/Where are the superifical forearm muscles
-insertion
-origin
Pronator teres
o=supracondylar ridge of humerus
i= middle anterior radius
Flexor carpi radialis
o=Common flexor tendon
i= base of 2 MT
Palmaris longus
o=Common flexor tendon
i= Palmar aponeurosis
Flexor carpi ulnaris
o=Common flexor tendon
i= pisiform and 4 and base of 5th MT
What are/Where are the intermediate forearm muscles
-insertion?
-origins
Intermediate = between so its insertion is in the middle of the finger aka intermediate)
Flexor digitorum superficialis
I= base of middle phalanx
o = 2:
- Radial Head (front of radius)
- humero-ulnar head (superior aspect of ulnar and medial epicondyle)
Divides into 4 tendons as it approaches capral tunnel, one onto each finger
What are/Where are the Deep forearm muscles
-insertion?
-origin
they are DEEP muscles and so they attach at the deepest (aka FURTHEST DOWN) point = end of finger
Flexor digitiorum profundus
I: base of distal phalanx
o=superior medial aspect of ulna and IM
Flexor pollicisi longus
I: base of distal phalanx
o= anterior radius
Pronator quadratus
I= Lateral side of radius
o= Medial side of ulnar
Superior view of the cross section through the right forearm
Lecture Slide
Label the entire arm with the nerve supply
Lecture
Median Nerve (anterior side) supplies ALL muscles of forearm EXCEPT FCU and medial 1/2 FDP (AKA THE ONES ON THE VERY ULNAR SIDE)
Ulnar nerve (anterior side): Medial 1/2 FDP and FCU
Radial (Posterior):
Superificial: Brachilais, Aconeous, ECRL, ECRB, ED, EDM, ECU
Deep: EI, EPL, EPB, APL, Supinator
Label the blood supply of forearm
- Brachial artery
- Radial
- Ulnar
There are recurrent branches (form anastemoses with collateral branches
What goes through carpal tunnel?
ESSENTIALLY ALL THE FLEXOR MUSCLES OF THE FOREARM EXCEPT FLEXOR CARPI ULNAR
FPL, FDS, FDP (btoh spilt into 4), FCR medial nerve
PL (above), Radial artery (around), ulnar artey (above), ulnar nerve (above) all dotn go through
Median nerve vs Ulnar nerve
- Both nerves have similar pattern when you get to wrist
- Medial nerve goes thorugh carpal tunnel, Ulnar doesnt.
3.Both have palmer cutaenoues branch, proper palmer digital nerves - Dorsal branch only from ulnar nerve
