Muscles Flashcards
In terms of anatomical identifiers, upper or more medial bony attachments are usually described as…
Proximal/superior
Origin
Lower or more lateral bony attachment is called…
Distal/inferior attachment
Insertion
Which part of a muscle is typically the most stationary?
Origin
How does bone attach to muscle?
Via a muscle tendon
Define muscle tendon. What type of tissue is it? Where do they attach to bone?
The non-fleshy, fibrous, dense regular connective tissue at the ends of a muscle.
At the bone, the fibres of the tendon are embedded in the periosteum. This anchors the tendon and spreads the force of contraction
The anterior tendons of the abdominal oblique muscles are flat, broad and thin. What are these flat tendons called?
Aponeurosis
Skeletal muscle exert their action on ____ which they must ____ to exert their action.
Joints
Cross
Some muscles cross one or more joints and exert their action on ____. Muscles only ___ on bones
Act on both joints
Muscles only pull
What does flexion and extension do to the length of muscle?
Flexion - bend/shorten
Extension - lengthen/extend
How many joints are crossed by the biceps brachii muscle? Name them
Three
Glenohumeral joint
Elbow
Radio-ulnar joint
What is the origin of the long head of the biceps brachii?
Supraglenoid tubercle above the socket of the scapula
What is the origin of the short head of the biceps brachii?
The coracoid process of the scapula
What is the insertion of the biceps brachii?
Radial tuberosity
How is the biceps brachii innervated?
Musculocutaneous nerve (C5-C6)
What 5 functions can the biceps brachii perform? Are they performed by the long or short head?
Abduction (long head)
Internal rotation (long head)
Adduction (short head)
Flexion (both heads)
Supination (both heads)
To which 2 bones are the tendons of biceps brachii attached?
Radius - radial tuberosity
Scapula - supraglenoid tubercle and coracoid process of scapula
What is the action of biceps brachii at each of the joints the muscle crosses - flexion or extension?
Elbow - flexion
Shoulder - flexion
How many joints are crossed by triceps brachii?
2
Elbow
Shoulder
When triceps contracts, i.e., the muscle itself shortens, what action will it have on each of the joints it crosses?
Elbow - extension at the elbow joint
Shoulder - extension at the shoulder joint
What muscle attaches to bone on either side of the midline (i.e. the medial sagittal plane)?
Diaphragm
When the diaphragm contracts, what happens to the muscle?
It descends and flattens
When the diaphragm’s domes contract, do they move superiorly or inferiorly?
Inferior
How does the diaphragm increase thoracic volume?
It’s like bellows. The contraction leads to a low pressure environment and the lungs fill the space
The deltoid has anterior, middle and posterior fibres. What shape of muscle is it and why?
Fan-shaped
Can “pull” on the shoulder joint in different directions
What function do the anterior, posterior and middle fibres of the deltoid do?
Anterior - flexion
Posterior - extension
Middle - abduction
Generally, what 4 functions can the deltoid do?
- Move arm in different directions
- Stabilise shoulder joint, preventing injuries
- Provide support when you carry things
- Side body lifting motions
Where is smooth muscle found?
Organs and BVs
Where is cardiac muscle found?
Heart wall