Untitled Quiz

Human Anatomy - Upper Limb - Forearm

• The forearm is subdivided into anterior and posterior compartments
• These compartments are separated by the radius, ulna, interosseous membrane, and deep fascia.
• The anterior compartment is more bulky than the posterior compartment because it houses muscles for flexing the wrist and fingers.

Forearm - Part 1 - Compartments

• Compartments: Forearm is divided into anterior, and posterior compartments. These compartments are anatomical divisions.
• Anterior Compartment: Contains muscles for flexing the wrist and fingers.
• Muscles: This section discusses muscles specifically located in the anterior compartment of the forearm.
• Short Questions: Includes brief questions relevant to the material.

Forearm (Compartments)

• The forearm contains anterior and posterior compartments.
• These compartments are divided by the radius, ulna, interosseous membrane, and deep fascia.
• The anterior compartment houses muscles for flexing the wrist and fingers and contains some important nerves and blood vessels.

Compartments of the Forearm

• The forearm's structure is divided into compartments: anterior and posterior.
• Structures like the radius, ulna, interosseous membrane, and deep fascia define these compartments.
• Diagrams visually illustrate the location and relationship of compartments.

Why the anterior compartment is more bulky than the posterior?

• The anterior compartment houses more muscles for flexion of the wrist and fingers.
• This greater muscle mass makes this compartment bulkier than the posterior compartment.

Anterior Compartment of the Forearm (Classification of Muscles)

• This section focuses on the muscles within the anterior compartment of the forearm, specifically classifying them.

Classification of Muscles of the Anterior Compartment of the Forearm

• Muscles in the anterior compartment are grouped into superficial and deep categories. This classification is based on their location relative to other structures.

Superficial Muscles of the Anterior Compartment of the Forearm

• Pronator teres (PT): A muscle responsible for pronation of the forearm, originating from the medial epicondyle (a bony prominence).
• Flexor carpi radialis (FCR): Flexes and abducts the wrist. Originates from the medial epicondyle.
• Flexor carpi ulnaris (FCU): Flexes and adducts the wrist. Originates from the medial epicondyle.
• Flexor digitorum superficialis (FDS): Flexes the middle phalanges of the fingers. Originates near the medial epicondyle.
• Palmaris longus (PL): Weakly flexes the wrist. Originates from the medial epicondyle.

Common Origin of the Forearm Muscles

• All muscles originate either superior to the medial epicondyle or from the upper end of the humerus
• These attachments are a common attachment point for several muscles involved in flexion of the forearm and wrist

Pronator Teres

• Origin:
  • superficial humeral head (common flexor origin)
  • deep ulnar head (medial border of the coronoid process of the ulna)
• Insertion: middle of the lateral surface of the radius
• Action
  • flexion of the elbow
  • pronation of the radio-ulnar joint (medial rotation of the forearm)

Relations (Nerves and Vessels)

• Median nerve typically passes between the two heads of pronator teres
• Deep head of pronator teres separates the median nerve from the ulnar artery.

Pronation and Supination

• These movements involve rotation of the forearm, leading to different orientations of the palm.
• Diagrams help illustrate the anatomical position and movement.

Flexor Carpi Radialis and Flexor Carpi Ulnaris

• Flexor Carpi Radialis (FCR) is responsible for wrist flexion and abduction. Its origin is near the humerus
• Flexor Carpi Ulnaris (FCU) is responsible for wrist flexion and adduction. Its origin is near the humerus

Attachments (Origin and Insertion)

• This section describes the origin points and insertions for each muscle
• Different parts of the forearm and hand are relevant

Attachments and Actions

• Flexion of the elbow joint: One of the actions performed by the anterior forearm muscles.
• Pronation of the radio-ulnar joint: Forearm rotation where the palm faces downward

Palmaris Longus

• A muscle with a short belly and long tendon, located in the anterior compartment.
• Tension of the palmaris aponeurosis is a primary function (helping form the palmar aponeurosis).
• Its position within the hand and forearm is crucial for the movement of the palm
• It is sometimes absent.

Flexor Digitorum Superficialis (FDS)

• This muscle flexes the wrist but also the proximal/middle phalanges of the fingers (medial 4)

Action of FCR and FCU

• FCR: Wrist flexion and abduction
• FCU: Wrist flexion and adduction

Relations of FCR and FCU

• FCR: Median nerve is medial to its tendon (related to the median nerve)
• FCU: Ulnar nerve passes between two heads (related to the ulnar nerve)

The tendon of the FCU is flattened

• The FCU tendon has a distinct anatomical structure.

4. Palmaris Longus

• Attachments & Actions:
• Flexion of the wrist
• Tension of the palmar aponeurosis.
• A short belly and a long tendon.
• The tendon of the Palmaris Longus muscle may be present or absent in some individuals

Deep Muscles of the Anterior Compartment

• This focus is on the deeper muscles situated within the anterior forearm compartment.
• The groups of muscles included discuss pronation and flexion of the wrist and fingers.

Origin and Insertion of Pronator Quadratus

• Pronator Quadratus: originates from the lower part of the anterior surface of the radius and inserts into the lower part of the anterior surface of ulna
• Pronator Quadratus is responsible for pronation of the forearm.

Attachments and Actions of Pronator Quadratus

• Pronation is the key function of this muscle
• Its attachments allow it to move the forearm.

Flexor Digitorum Profundus and Flexor Pollicis Longus

• This describes origin, insertion, and actions of these deep muscles in the anterior forearm compartment
• Flexor pollicis longus is also described

Insertion of FPL

• Tendon of FPL is unipennate
• Insertion is on the base of the terminal phalanx of the thumb.

Actions of FPL and FDL

• FPL flexes all joints of the thumb
• FDL flexes the proximal and distal interphalangeal joints and the metacarpophalangeal joints, notably for medial 4 fingers.
• Both are responsible for flexing specific structures in the hand and wrist.

How the FDS and FDP Tendons Reach the Distal Phalanx

• FDS tendon is located in the superficial group, while the FDL tendon is found in the deep group.
• The FDS tendon splits to create perforations for FDP tendons to pass through.

Relation Between FDS and FDP

• FDS tendon splits to form perforations through which the FPD tendon passes.
• The relationship is primarily located at the proximal phalanx level.

Deep Muscles of the Anterior Forearm - Nerves

• This describes the nerves supplying the deep muscles within the anterior compartment of the forearm.

Nerves of the Anterior Compartment

• This focuses on the nerves involved in supplying the anterior compartment of the forearm.

Course of Median, Ulnar, and Radial Nerves

• This describes the path of the median, ulnar, and radial nerves through the forearm.

Branches of the Median and Ulnar Nerves

• This explains the various branches from the median and ulnar nerves, delineating their roles and locations within the forearm and hand.

Anterior Interosseous Nerve

• A branch of the median nerve, running through the interosseous membrane.
• Supplies the flexor pollicis longus and flexor digitorum profundus muscles (majority of the flexors of the index, middle, ring and little fingers) and the pronator quadratus.

Branches (Nerves)

• Provides nervous supply to specific muscles like flexors, facilitating movement.