Anatomy of muscles II Flashcards
what are the movements of the trunk?
flexion/ extension, lateral flexion, twist rotation
ABDOMINAL MUSCLES what are the 4?
- External oblique
- Internal oblique
- Rectus abdominus
- transverse abdominus
- External oblique - where and origin
- Most superficial of the abdominal muscles
- Small, flat muscle running inferior- medially (hands in pocket)
- Allows trunk to twist/flex and rotate
Origin - serration from ribs 5-12
insertion - illiac crest, posteriorly, anteriorly forms the inguinal ligament & rectus sheath
- Internal oblique - where and origin
- Second most superficial of the abdominal muscles, just inside the hip bones
- Opposing twisting motion to ext. obliques
origin - thoracolumber fascia, iliac crest, inguinal ligament
insertion - 10th - 12th ribs and linear alba
- Rectus abdominus - where and origin
Small, flat muscle running superior-medially (hands on chest)
Connective tissue bands (tendinous intersections) separate into distinct muscle ‘bellies’
Linea alba separates left and right abdominis muscles
Externally visible as the “six pack”
Flexion of trunk
Origin - Cartilage ribs 5-7
Insertion - Pubic symphysis and pubic bone
- Transverse abdominus
Lies deep to the int. obliques (deepest layer)
- Fibres run transversely (hands on hips)
- “corset” muscle
- Stabilizes trunk and maintains internal abdominal pressure
- Assists in parturition
Origin - rib cartilage 7-12, thoracolumber fascia, iliac crest, inguinal ligament
Insertion - abdominal sheath, linear alba
What 4 muscles are located on the anterior chest wall?
- Pectoralis major
- Pectoralis minor
- Serratus anterior
- Subclavius
Pectoralis major location and what movement does it involve
- Large triangle shaped muscle
- Active during forced/deep inspiration
- Involved on adduction and medial rotation of the arm
origin - medial 1/2 of clavicle, sternum, cartilages of ribs 1-7, and aponeurosis of external oblique muscle
Insertion - distal to greater tuberosity of humerus
Pectoralis Minor location and movement
• Thin, triangular muscle under the pectoralis major • Functions mainly involve movements of the scapula o Stabilization o Depression o Abduction o Internal & downward rotation also accessory muscle for inspiration origin - ribs 3-5 insertion - coracoid process of scapula
Serratus anterior
•Muscle of multiple serration, forming the side of the chest
•Involved in forward movement of the scapula, forward rotation of the arm (lifting arm overhead)
•Also supports breathing
origin - anterior part of ribs 1-8
insertion - scapula
Subclavius
• Small muscle between the clavicle and 1st rib
• Forms the anterior wall of the armpit (“axilla”)
• Stabilizes the clavicle – responsible for depression of clavicle and elevation of 1st rib
• Protects underlying brachial plexus (collection of important nerves) from a broken clavicle (most frequent
origin - rib 1
insertion - clavicle
What is the function of the intercostal muscles?
• Help form and move the chest wall – expansion and shrinkage of chest cavity during breathing
What function doe the external intercostal do, and what does the internal intercostals do?
External intercostals:
•Pull ribs together, rising rib cage during forced expiration
Internal intercostals:
•Depress the rib cage during forced expiration
•Fibres run 90’ to external intercostals
External intercostals are active in normal respiration, whereas the internal intercostals are only active during forced respiration
What are the two shoulder muscles?
- deltoid
2. rotator cuff
What movement does deltoid allow?
allows flexion and inward rotation of shoulder, and abduction and extension of arm
origin - lateral third of clavicle, acromion, and inferior boarder of scapula spine
insertion - deltoid tuberosity of the humerus
what 4 muscles are part of the rotator cuff that stabilise the shallow shoulder joint?
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
what are the 4 muscles in the back (superficial group)
Back muscle
- Trapezius
- Rhomboid Major and Minor
- Latissimus Dorsi
- Levator scapulae
- Trapezius and its movements
- Large flat muscle of the back
- Most superficial muscle of the back
- involved in scapula and neck movement (shoulder girdle
it carries out elevation, adduction, upward and downward rotation, and depression of your scapula
- Rhomboid major and minor
• Two rhombus-shaped muscles inferior to the trapezius
• Rhomboid minor is superior to rhomboid major
•involved in scapula movements
Adduction, Elevation, downward rotation
- Lattismus dorsi
•Thin, triangular muscle of the back
•Involved in adduction, extension and internal rotation of the arm
•Movements of the trunk and scapula
•Role in extension and lateral flexion of lumbar spine
origin - T7-L5 vertebrae, sacrum, iliac crest, thoracolumber fascia, scapula
insertion - intertubercular sulcus of the humerus
- Levator scapulae
• Small muscle under the trapezius
• Elevates and rotates the scapula, as well as assisting flexion and extension of the cervical spine
Eg. Shrug shoulders
Two compartments of the arm
- anterior compartment (flexors) - what are the 2 flexors
- posterior compartment (extensor) - what is the extensor?
- flexor - bicep brachii, brachialis
2. extensor - tricep brachii
- bicep brachii (long and short) - “BI” = two heads
and its movement
origin and insertion
o Flexes the elbow
o Supinates the arm
o Flexes the shoulder (weakly
Origin: long head = supraglenoid tuberosity
Short head= coracoid process
Insertion: Radial tuberosity on radius (anterior)
- brachialis - movement, origin and insertion
•Small, flat muscle
•Large cross-sectional area – more strength than biceps brachii!
•Flexes the elbow
•Common site of injury for climbers
origin - anterior surface of humerus, distal to deltoid insertion - coranoid process of ulna
FLEXOR 1. bicep brachii (long and short) - “BI” = two heads
and its movement
origin and insertion
o Flexes the elbow
o Supinates the arm
o Flexes the shoulder (weakly
Origin: long head = supraglenoid tuberosity
Short head= coracoid process
Insertion: Radial tuberosity on radius (anterior)
FLEXOR 2. brachialis - movement, origin and insertion
•Small, flat muscle
•Large cross-sectional area – more strength than biceps brachii!
•Flexes the elbow
•Common site of injury for climbers
origin - anterior surface of humerus, distal to deltoid insertion - coranoid process of ulna
EXTENSOR 1. tricep brachii “tri” = has 3 heads
- Long: O= infranglenoid tubercle of the scapula
- Lateral: O = back of the humerus. Fuses with the long head
- Medial: O = back of the humerus (hidden under the other heads)
photo
The Bicep tendon inserts into the radius at the Coronoid Process
The Tricep tendon inserts into the Olecranon of the ulna
photo
What do the muscles of the forearm do?
they move the wrist and hand
where do all the main muscles of the anterior compartment originate from?
The main muscles in the anterior compartment all originate from the medial epicondyle of the humerus
what are the 4 main muscles of the anterior compartment?
- Flexorcarpi radialis
- Flexor carpi ulnaris
- Palmaris longus
- Pronator teres
what are the 4 main muscles of the anterior compartment?
- Flexor carpi radialis
- Flexor carpi ulnaris
- Palmaris longus
- Pronator teres
- Flexor Carpi Radialis
movement and insertion point
•Flexion and abduction at the wrist
Insertion – Lateral capals and 5th metacarpal bone
- Flexor Carpi Ulnaris
movement and insertion point
- Flexion & adduction of the wrist
* Insertion – Lateral carpals and 5th metacarpal bone
- Palmaris longus
movement and insertion point
•Flexion at the wrist
•Absent in 13% of people!
•Tendon passes on front of the flexor retinaculum
Insertion: Palmar aponeurosis
- pronator teres
movement insertion and origin (2points)
Pronates the forearm •Has two heads of origin Origin 1: medial epicondyle of humerus Origin 2: coranoid process or ulna Insertion: radius shaft Supination and pronation
FLEXOR posterior compartment of forearm
- Brachioradialis
•Flexes elbow
•Pronation and supination of forearm
Origin – lateral supracondylar ridge
Insertion- Radial styloid process
EXTENSOR posterior compartment of forearm
- Extensor carpi radialis
- Extends and abducts the wrist
- Has two parts: longus and brevis
- Very important in making a fist
Longus = longest Brevis = biggest origin - lateral supracondylar ridge origin - lateral epicondyle of humerus insertion - 2nd and 3rd metacarpals (same as flexor carpi radialis)
- Extensor carpi ulnaris
• Extends and abducts the wrist • Extends elbow • Very important in making a fist origin - Lateral epicondyle of humerus insertion - 5th metacarpal
- Extensor digitorum
4. Extensor digiti minimi
• Four tendons
• Extensor of the wrist and fingers
4. Extensor digiti minimi
• Extends and abducts the little finger
3. origin - lateral epicondyle of humerus
3. insertion - medial 4 digits
4. origin - lateral epicondyle of humerus
4. insertion - 5th digit
- Anconeus
• Extends elbow and pronate forearm
• Used when carrying an object in forearms
origin - posterior surface of lateral condyle
insertion - olecranon and shaft of ulna
