ANAT3008
Upper Limb
» Function of the Upper Limb
# Major Functions of the Upper Limb
Manipulation – lever with hand on the end
̶ If an action is made on the external environment or an object in the external environment and
the object is effected, it is manipulation.
̶ However if the body moves, it is locomotion.
Sensation
Communication (e.g. hand gestures)
Cosmetic (e.g. body image)
# Evolutionary Considerations
Analogies.
̶ Across species, a variety of structures perform the manipulation function of the upper limb (e.g.
beaks, jaws, tails, limbs front and back).
̶ Structures that have a similar function are said to be analogous (e.g. hand and bird’s beak)
Homologies.
̶ The upper (anterior) limb across species is involved in many different sorts of locomotor and
manipulative functions. Mostly used in locomotion: many forms, flight, swimming, climbing.
̶ Structures that have a similar developmental origin are said to be homologous (e.g. hand and
bird’s wings).
Upper and lower limbs are serially homologous: each is composed of parts which are
repeated in the other, i.e. shared properties due to comparable development
Humerus and femur are serially homologous
Primates.
̶ In primate evolution the initial adaptation of the upper limb is arboreal (climbing trees)
̶ Later, and in particular with hominid (humans and their immediate ancestors) evolution, the
upper limb shows an increasing specialisation for precision manipulation.
# The Upper Limb in Human Development
Locomotion.
̶ In adult humans the upper limb is not habitually used in locomotion, however for a brief period
in infancy it is, crawling.
̶ However in some occupational and sporting activities, the upper limb is utilised in a locomotory
way e.g. swimming.
Grasp Development.
̶ In the development of manipulative skills, the power grip (fist) develops earlier than the
precision grip (writing grip).
̶ Both are co-ordinated with the development of other limb and body movements, in particular
eye movements (eye hand co-ordination).
# Contribution of Individual Regions to Manipulation
Heirarchy of upper limb function: reach, force transfer, movement, grip/grasp
Reach.
̶ Arm length determines reach, maximum length, and effective length.
Force Transfer.
̶ Stability is the lack of deformity or movement in a structure when force is applied it.
1
, ̶ Stability leads to the force being transferred to another location.
̶ It facilitates resisting or absorbing external forces such as gravity and during bodily impact with
the environment.
̶ It can also apply to resisting or absorbing forces in the internal environment such as when
muscles contract, such resistance or force transfer allowing the muscles to act at a distance.
̶ Forces that compress joints are termed impaction forces, forces that pull joints apart,
disimpaction forces. Both sorts act on the upper limb.
̶ All regions contribute to force transfer in the upper limb.
̶ Stabilising sometimes to the point of fixation at joints is as important in manipulation as is
movement.
̶ For example stabilising the shoulder and elbow joints or regions in fine manipulation or the
wrist in the power grip.
Movement.
̶ Increased mobility is usually associated with synovial joints, a greater number of joints and the
amount of curvature of the articular surfaces.
̶ Muscle size usually determines power and numbers precision. Preciseness of attachments and
the size of the motor units also effect precision. The positioning of muscles with regard to joints
effects the direction of movements.
Grip.
̶ Friction. Palmar and digit skin, finger pads.
Shoulder Region.
̶ The scapula has a muscular attachment to thorax with 6 major directions (3 axis) of movement.
̶ The shoulder joint, a shallow ball and socket joint with a loose capsule, also has 6 major
directions of movement (3 axis).
̶ When the shoulder muscles act isotonically the scapula and the shoulder joint provide a large
range of movement to the upper limb as a whole and the hand in particular. Rotation of
shoulder joint also contributes to the movement of the plane of the hand. The muscles which
produce this mobility are all located on one side of the joint. They are all relatively flat and
somewhat triangular in shape and as a group form a partial cone with its apex around the
shoulder and scapula.
̶ When the shoulder muscles act isometrically the shoulder region provides a stable base for the
hand particularly for more precision movements.
Arm and elbow.
̶ The arm muscles act on the elbow joint and also contribute to supination at the radio-ulna
joints.
̶ The elbow joint is a stable hinge joint allowing flexion and extension.
̶ This allows the hand to move to and from the body surface and alters the effective length of
the limb.
̶ In particular it allows the hand access to most of the body surface and allows things to be
brought to and from the body without using locomotion such as in doing things while seated eg
eating.
̶ It also facilitates hand and eye co-ordination particularly the placing of objects nearer to eyes in
precision activities.
̶ It also allows reaching around corners and bending of the arms to carry things.
Forearm.
̶ The two radio-ulnar joints are pivot joints allowing pronation, and supination.
̶ Along with the shoulder joint they allow the plane of the hand to move, rotate, through 360
degrees and enable the plane of the hand to be altered even when the elbow is flexed.
̶ The ulnar is relatively fixed at the elbow and the hand attached to the radius, hence in
pronation and supination the radius rotates around the ulna. The distal upper limb is usually
carried and used precisely in the pronated position.
2
, ̶ The forearm muscles used in pronation, and supination pass across the long axis of the
forearm.
̶ Most of the remaining forearm muscles have a proximal muscular part and a long narrow distal
tendinous part which runs parallel to the axis of the forearm and then passes into the hand.
They are descriptively called the extrinsic hand muscles and act to flex and extend the wrist
and the digits and are important in the power grip.
Wrist.
̶ The wrist joint is an ellipsoid joint with four major directions of movement – allows for
circumduction
̶ In the power grip the hand is stabilised at the wrist and wrist joint extension assists power in
long flexors.
̶ In the precision grip the wrist joint allows the hand to adjust without moving the whole upper
limb.
Hand.
̶ Has many small bones and joints.
̶ Many small intrinsic hand muscles along with the many tendons of the extrinsic hand muscles.
Overall about 30 muscles, some of which have several tendons, are attached to the hand.
̶ The surface of the hand is also specially adapted. The proximal parts of the upper limb locate
and orientate the hand, the hand itself is particularly used for grip and grasp
# The Hand
Grasp (flexion, opposition)
̶ Power grip, mainly medial four digits, extrinsic hand muscles, assisted by wrist extension,
palmar skin adaptations.
̶ Precision grip, usually the two most lateral digits, thumb vital, intrinsic hand muscles, finger
pads.
Subregions
̶ Overall the hand has a stable proximal cupped platform formed by the carpal and medial four
meta-carpal bones.
̶ Distally are four opposing bendable spreadable digits (due to the many joints) and a fifth
bendable mobile digit, the thumb, set at right angles to the platform and other digits, which can
oppose the platform and the other digits.
̶ The distal end of each digit has a specialised region containing the finger pads and nails
Bones
̶ Bones allow force transfer.
̶ Even though the forces generated in the hand in most habitual use is not great this function is
important.
Joints
̶ The proximal joints of the hand in the palm region allow little movement.
̶ Those more distally placed all allow flexion.
̶ In addition the metacarpal-phalangeal joints of the medial four digits allow lateral movement
̶ The first carpo-metacarpal joint (saddle joint) allows the thumb to rotate.
̶ Mobility of the hand is located in the middle of the hand
Muscles
̶ Within the hand the extrinsic muscles are reduced in bulk to tendons which are held close to
the bones by the flexor retinaculum and the fibrous flexor sheaths.
̶ The intrinsic muscles are positioned along the edges of the hand or deep between the
metacarpal bones.
̶ They have small motor units and a large representation on the primary motor cortex of the
brain.
̶ They are important in precision movements.
3
, Nerves
̶ Small motor units in intrinsic hand muscles.
̶ Good proprioception for the digits and palmar cutaneous sensation particularly to the finger
pads.
̶ Relatively large representation in the cerebral cortex.
Skin
̶ Skin on the palmar surface is adapted for grip.
Thick, held to underlying tissue, ridges, no hair, no sebaceous glands, many sweat glands
̶ Fingerpads: palmar surface, large sensory innervation, skin specialized, soft due to underlying
adipose tissue, moulding.
̶ Finger nails: assist in some manipulations.
Connective Tissue
̶ Binds the palmar skin.
̶ Holds the long tendons against the bones.
̶ Helps form the finger pads.
Region(s) Bones. Joints. Muscles. Function in
Manipulation.
Shoulder Clavicle, Scapula/Thorax. Shoulder. Spherical range.
scapula, Shoulder joint. Rotation.
proximal
humerus
Arm, Humerus, Elbow joint Anterior & Posterior Arm. Hand to and from
Elbow proximal the body and around
radius & ulna. corners.
Forearm Radius & ulna Radioulnar joints Anterior and Posterior Rotation of hand.
Forearm.
Wrist Distal radius Wrist joint Anterior and Posterior Adjust hand.
& ulna, Forearm.
Proximal
carpal
Hand Carpal, Intercarpal joints. Intrinsic Hand Muscles. Grasp. Power &
metacarpal, Carpometacarpal joints. Tendons of some Precision.
phalanges. Metacarpophalangeal forearm muscles (EHM).
joints
Interphalangeal joints.
4
Upper Limb
» Function of the Upper Limb
# Major Functions of the Upper Limb
Manipulation – lever with hand on the end
̶ If an action is made on the external environment or an object in the external environment and
the object is effected, it is manipulation.
̶ However if the body moves, it is locomotion.
Sensation
Communication (e.g. hand gestures)
Cosmetic (e.g. body image)
# Evolutionary Considerations
Analogies.
̶ Across species, a variety of structures perform the manipulation function of the upper limb (e.g.
beaks, jaws, tails, limbs front and back).
̶ Structures that have a similar function are said to be analogous (e.g. hand and bird’s beak)
Homologies.
̶ The upper (anterior) limb across species is involved in many different sorts of locomotor and
manipulative functions. Mostly used in locomotion: many forms, flight, swimming, climbing.
̶ Structures that have a similar developmental origin are said to be homologous (e.g. hand and
bird’s wings).
Upper and lower limbs are serially homologous: each is composed of parts which are
repeated in the other, i.e. shared properties due to comparable development
Humerus and femur are serially homologous
Primates.
̶ In primate evolution the initial adaptation of the upper limb is arboreal (climbing trees)
̶ Later, and in particular with hominid (humans and their immediate ancestors) evolution, the
upper limb shows an increasing specialisation for precision manipulation.
# The Upper Limb in Human Development
Locomotion.
̶ In adult humans the upper limb is not habitually used in locomotion, however for a brief period
in infancy it is, crawling.
̶ However in some occupational and sporting activities, the upper limb is utilised in a locomotory
way e.g. swimming.
Grasp Development.
̶ In the development of manipulative skills, the power grip (fist) develops earlier than the
precision grip (writing grip).
̶ Both are co-ordinated with the development of other limb and body movements, in particular
eye movements (eye hand co-ordination).
# Contribution of Individual Regions to Manipulation
Heirarchy of upper limb function: reach, force transfer, movement, grip/grasp
Reach.
̶ Arm length determines reach, maximum length, and effective length.
Force Transfer.
̶ Stability is the lack of deformity or movement in a structure when force is applied it.
1
, ̶ Stability leads to the force being transferred to another location.
̶ It facilitates resisting or absorbing external forces such as gravity and during bodily impact with
the environment.
̶ It can also apply to resisting or absorbing forces in the internal environment such as when
muscles contract, such resistance or force transfer allowing the muscles to act at a distance.
̶ Forces that compress joints are termed impaction forces, forces that pull joints apart,
disimpaction forces. Both sorts act on the upper limb.
̶ All regions contribute to force transfer in the upper limb.
̶ Stabilising sometimes to the point of fixation at joints is as important in manipulation as is
movement.
̶ For example stabilising the shoulder and elbow joints or regions in fine manipulation or the
wrist in the power grip.
Movement.
̶ Increased mobility is usually associated with synovial joints, a greater number of joints and the
amount of curvature of the articular surfaces.
̶ Muscle size usually determines power and numbers precision. Preciseness of attachments and
the size of the motor units also effect precision. The positioning of muscles with regard to joints
effects the direction of movements.
Grip.
̶ Friction. Palmar and digit skin, finger pads.
Shoulder Region.
̶ The scapula has a muscular attachment to thorax with 6 major directions (3 axis) of movement.
̶ The shoulder joint, a shallow ball and socket joint with a loose capsule, also has 6 major
directions of movement (3 axis).
̶ When the shoulder muscles act isotonically the scapula and the shoulder joint provide a large
range of movement to the upper limb as a whole and the hand in particular. Rotation of
shoulder joint also contributes to the movement of the plane of the hand. The muscles which
produce this mobility are all located on one side of the joint. They are all relatively flat and
somewhat triangular in shape and as a group form a partial cone with its apex around the
shoulder and scapula.
̶ When the shoulder muscles act isometrically the shoulder region provides a stable base for the
hand particularly for more precision movements.
Arm and elbow.
̶ The arm muscles act on the elbow joint and also contribute to supination at the radio-ulna
joints.
̶ The elbow joint is a stable hinge joint allowing flexion and extension.
̶ This allows the hand to move to and from the body surface and alters the effective length of
the limb.
̶ In particular it allows the hand access to most of the body surface and allows things to be
brought to and from the body without using locomotion such as in doing things while seated eg
eating.
̶ It also facilitates hand and eye co-ordination particularly the placing of objects nearer to eyes in
precision activities.
̶ It also allows reaching around corners and bending of the arms to carry things.
Forearm.
̶ The two radio-ulnar joints are pivot joints allowing pronation, and supination.
̶ Along with the shoulder joint they allow the plane of the hand to move, rotate, through 360
degrees and enable the plane of the hand to be altered even when the elbow is flexed.
̶ The ulnar is relatively fixed at the elbow and the hand attached to the radius, hence in
pronation and supination the radius rotates around the ulna. The distal upper limb is usually
carried and used precisely in the pronated position.
2
, ̶ The forearm muscles used in pronation, and supination pass across the long axis of the
forearm.
̶ Most of the remaining forearm muscles have a proximal muscular part and a long narrow distal
tendinous part which runs parallel to the axis of the forearm and then passes into the hand.
They are descriptively called the extrinsic hand muscles and act to flex and extend the wrist
and the digits and are important in the power grip.
Wrist.
̶ The wrist joint is an ellipsoid joint with four major directions of movement – allows for
circumduction
̶ In the power grip the hand is stabilised at the wrist and wrist joint extension assists power in
long flexors.
̶ In the precision grip the wrist joint allows the hand to adjust without moving the whole upper
limb.
Hand.
̶ Has many small bones and joints.
̶ Many small intrinsic hand muscles along with the many tendons of the extrinsic hand muscles.
Overall about 30 muscles, some of which have several tendons, are attached to the hand.
̶ The surface of the hand is also specially adapted. The proximal parts of the upper limb locate
and orientate the hand, the hand itself is particularly used for grip and grasp
# The Hand
Grasp (flexion, opposition)
̶ Power grip, mainly medial four digits, extrinsic hand muscles, assisted by wrist extension,
palmar skin adaptations.
̶ Precision grip, usually the two most lateral digits, thumb vital, intrinsic hand muscles, finger
pads.
Subregions
̶ Overall the hand has a stable proximal cupped platform formed by the carpal and medial four
meta-carpal bones.
̶ Distally are four opposing bendable spreadable digits (due to the many joints) and a fifth
bendable mobile digit, the thumb, set at right angles to the platform and other digits, which can
oppose the platform and the other digits.
̶ The distal end of each digit has a specialised region containing the finger pads and nails
Bones
̶ Bones allow force transfer.
̶ Even though the forces generated in the hand in most habitual use is not great this function is
important.
Joints
̶ The proximal joints of the hand in the palm region allow little movement.
̶ Those more distally placed all allow flexion.
̶ In addition the metacarpal-phalangeal joints of the medial four digits allow lateral movement
̶ The first carpo-metacarpal joint (saddle joint) allows the thumb to rotate.
̶ Mobility of the hand is located in the middle of the hand
Muscles
̶ Within the hand the extrinsic muscles are reduced in bulk to tendons which are held close to
the bones by the flexor retinaculum and the fibrous flexor sheaths.
̶ The intrinsic muscles are positioned along the edges of the hand or deep between the
metacarpal bones.
̶ They have small motor units and a large representation on the primary motor cortex of the
brain.
̶ They are important in precision movements.
3
, Nerves
̶ Small motor units in intrinsic hand muscles.
̶ Good proprioception for the digits and palmar cutaneous sensation particularly to the finger
pads.
̶ Relatively large representation in the cerebral cortex.
Skin
̶ Skin on the palmar surface is adapted for grip.
Thick, held to underlying tissue, ridges, no hair, no sebaceous glands, many sweat glands
̶ Fingerpads: palmar surface, large sensory innervation, skin specialized, soft due to underlying
adipose tissue, moulding.
̶ Finger nails: assist in some manipulations.
Connective Tissue
̶ Binds the palmar skin.
̶ Holds the long tendons against the bones.
̶ Helps form the finger pads.
Region(s) Bones. Joints. Muscles. Function in
Manipulation.
Shoulder Clavicle, Scapula/Thorax. Shoulder. Spherical range.
scapula, Shoulder joint. Rotation.
proximal
humerus
Arm, Humerus, Elbow joint Anterior & Posterior Arm. Hand to and from
Elbow proximal the body and around
radius & ulna. corners.
Forearm Radius & ulna Radioulnar joints Anterior and Posterior Rotation of hand.
Forearm.
Wrist Distal radius Wrist joint Anterior and Posterior Adjust hand.
& ulna, Forearm.
Proximal
carpal
Hand Carpal, Intercarpal joints. Intrinsic Hand Muscles. Grasp. Power &
metacarpal, Carpometacarpal joints. Tendons of some Precision.
phalanges. Metacarpophalangeal forearm muscles (EHM).
joints
Interphalangeal joints.
4
