Muscle Library

The Muscle Library, A–Z

Every muscle page in the library, alphabetically. Each covers where that muscle sends pain, what the pattern feels like, what it gets mistaken for, and how I examine and treat it. If you know where it hurts but not which muscle, start with the Pain Finder instead. For the acupuncture points and motor points used on these muscles, see the Orthopedic Points reference.

By Region

The seven regions of the Pain Finder, each with every muscle in the library for that region. The full list, A to Z, follows below.

Head & Neck

Upper Trapezius: Upper trapezius trigger points and referral pattern: neck pain climbing to the temple and behind the eye, the classic tension headache path.

Sternocleidomastoid: SCM trigger points and referral pattern: a front-of-neck muscle producing forehead, eye, ear, and cheek pain, with dizziness described on head turns.

Suboccipitals: Suboccipital trigger points and referral pattern: a band of headache from the skull base to the eye and forehead, felt inside the head.

Levator Scapulae: Levator scapulae trigger points and referral pattern: the stiff neck muscle, pain at the angle of the neck with blocked same-side rotation.

Scalenes: Scalene trigger points and referral pattern: neck muscles producing chest, upper back, and arm symptoms into the thumb side of the hand.

Temporalis: Temporalis trigger points and referral pattern: temple headache, pain along the eyebrow, and upper tooth sensitivity.

Masseter: Masseter trigger points and referral pattern: jaw and cheek pain, tooth sensitivity, and pain over the TMJ that mimics joint problems.

Splenius Capitis: Splenius capitis trigger points refer headache to the top of the head, on one side.

Splenius Cervicis: Through the head to the back of the eye, with blurred vision, and at the angle of the neck.

Semispinalis Capitis: A band of headache around the side of the head to the temple and forehead, and a numb scalp.

Longus Colli and Longus Capitis: The deep neck flexors: front-of-neck pain that refers to the ear and beside the eye, a tight throat after whiplash, a head that is hard to lift.

Digastric: Behind the ear and the upper neck, aching lower front teeth, and a lump in the throat when swallowing.

Medial Pterygoid: Medial pterygoid trigger points refer pain deep into the ear, the throat, and the angle of the jaw, with pain on swallowing.

Lateral Pterygoid: Lateral pterygoid trigger points refer pain deep into the jaw joint and across the cheek where the sinus sits, with a jaw that clicks or drifts.

Occipitofrontalis: A forehead headache above one eyebrow, and a back of the head that cannot rest on a pillow.

Orbicularis Oculi: Along the nose, the cheek below the eye, and the upper lip, with a twitching eyelid.

Zygomaticus and Buccinator: Sinus-like pain from the nose to the forehead, and deep cheek and jaw pain when chewing.

Platysma: A prickling on the skin of the lower jaw, chin, and cheek, from the sheet muscle of the front of the neck.

Shoulder & Upper Back

Infraspinatus: Infraspinatus trigger points and referral pattern: a shoulder blade muscle producing deep front-of-shoulder pain that runs down the arm.

Supraspinatus: Supraspinatus trigger points and referral pattern: a deep ache at the outer shoulder running down the outside of the arm toward the elbow.

Subscapularis: Subscapularis trigger points and referral pattern: severe back-of-shoulder pain with a documented band of referral at the wrist.

Deltoid: Deltoid trigger points and referral pattern: pain felt locally in the shoulder cap itself, worse with movement.

Rhomboids: Rhomboid trigger points and referral pattern: aching along the inner edge of the shoulder blade that persists at rest.

Scalenes: Scalene trigger points and referral pattern: neck muscles producing chest, upper back, and arm symptoms into the thumb side of the hand.

Teres Minor: Teres minor trigger points produce one deep, coin-sized spot of pain at the back of the shoulder, the fourth rotator cuff muscle.

Teres Major: Teres major trigger points refer a deep ache to the back of the shoulder and down the back of the upper arm, worst reaching up and forward.

Latissimus Dorsi: Latissimus dorsi trigger points cause a constant mid-back ache at the lower shoulder blade, spilling down the inner arm to the ring and little fingers.

Middle Trapezius: Middle trapezius trigger points cause burning between the shoulder blades and aching at the point of the shoulder.

Lower Trapezius: Lower trapezius trigger points refer pain upward: suprascapular ache, shoulder-point pain, and a burning line along the inner shoulder blade.

Pectoralis Minor: Pectoralis minor trigger points refer pain to the front of the shoulder and upper chest, with tingling down the inner arm to the ring and little fingers.

Subclavius: From the collarbone down the front of the arm to the thumb and first two fingers, with the elbow and wrist skipped.

Serratus Posterior Superior: A deep ache under the shoulder blade that runs down the back of the arm to the little finger.

Coracobrachialis: The front of the shoulder and a line down the back of the arm to the back of the hand, worst reaching behind the back.

Arm & Hand

Triceps: Triceps trigger points and referral pattern: aching down the back of the arm to the elbow and dorsal forearm.

Brachioradialis: Brachioradialis trigger points and referral pattern: outer-elbow ache running down the thumb side of the forearm to the base of the thumb.

Forearm Extensor Group: Forearm extensor trigger points and referral pattern: outer-elbow pain spreading over the back of the forearm to the wrist and hand.

Forearm Flexor Group: Forearm flexor trigger points and referral pattern: volar wrist and palm pain from the wrist and finger flexors, often mistaken for carpal tunnel.

Thumb Muscles: Adductor and opponens pollicis trigger points: aching at the base of the thumb and along the thumb, often labeled texting thumb.

Abductor Pollicis Longus and Extensor Pollicis: The back of the wrist on the thumb side and the back of the thumb, the de Quervain the splint did not fix.

Biceps Brachii: Biceps brachii trigger points refer superficial pain to the front of the shoulder, often misread as bicipital tendinitis.

Brachialis: Pain at the base of the thumb from the upper arm, with a numb back of the thumb.

Anconeus: Pain at the outside of the elbow that stays at the elbow, worst pushing up from a chair.

Supinator: The outside of the elbow and the web of the thumb, the tennis elbow that tendon treatment does not fix.

Pronator Teres: Deep in the front of the forearm and wrist on the thumb side, with a numb palm mistaken for carpal tunnel.

Palmaris Longus: A prickling, needle-like pain in the middle of the palm and the base of the thumb.

Extensor Carpi Radialis Longus and Brevis: Tennis elbow at the outer elbow and the back of the wrist and hand, with a grip that drops things.

Extensor Digitorum: Down the back of the forearm into the back of one finger, with stiff fingers in the morning.

Extensor Indicis: The back of the wrist and the thumb side of the back of the hand, worst pointing and clicking.

Flexor Carpi Radialis: The front of the wrist crease on the thumb side, worst pushing up from a chair.

Flexor Carpi Ulnaris: The front of the wrist on the little-finger side, with tingling in the ring and little fingers.

Flexor Pollicis Longus: Along the palm side of the thumb to the tip, worst pressing the thumb on a pen or a phone.

Interossei of the Hand: Along the side of one finger and in the thumb web, with an aching index finger.

Lumbricals of the Hand: Pain along the side of one finger from the palm, worst in the writing position.

Hypothenar Muscles: The fleshy mound below the little finger and the outer side of the little finger, worst cupping the hand.

Torso & Abdomen

Pectoralis Major: Pectoralis major trigger points and referral pattern: chest and front-of-shoulder pain running down the inner arm.

Serratus Anterior: Serratus anterior trigger points and referral pattern: side-of-chest pain at mid-rib level with referral down the inner arm.

Rectus Abdominis: Rectus abdominis trigger points and referral pattern: pain around the navel, horizontal back bands, and a lower-right zone that mimics appendicitis.

Abdominal Obliques: Abdominal oblique trigger points and referral pattern: heartburn-like upper abdominal pain and groin pain from the lateral abdominal wall.

Sternalis: Deep pain behind the breastbone that does not change with breathing, a cardiac mimic.

Intercostals: Sharp pain in one rib space that a breath, a cough, or a twist finds.

Diaphragm: A stitch along the front lower ribs on a deep breath, and an ache at the top of the shoulder.

Transversus Abdominis: A band of pain across the upper abdomen just under the ribs, worst coughing or bracing.

Pyramidalis: Midline pain just above the pubic bone, mistaken for a bladder or gynecologic problem.

Iliocostalis Thoracis: Beside the spine in the mid back, up toward the shoulder blade, and around into the chest wall.

Serratus Posterior Inferior: A nagging ache over the lower ribs at the back that stays put.

Iliopsoas: Iliopsoas trigger points: vertical low back pain and front-of-hip pain from the primary hip flexor.

Erector Spinae: Erector spinae trigger points: referral below their own level, broad stiffness, a band across the back.

Low Back & Hip

Quadratus Lumborum: Quadratus lumborum trigger points and referral pattern: deep, aching low back pain into the SI region, buttock, and iliac crest.

Gluteus Medius: Gluteus medius trigger points and referral pattern: pain over the belt line, sacrum, and outer buttock read as low back pain.

Gluteus Minimus: Gluteus minimus trigger points: referral down the leg to the ankle, the classic sciatica mimic.

Piriformis: Piriformis trigger points and referral pattern: deep buttock ache with sitting, possible sciatic nerve irritation.

Iliopsoas: Iliopsoas trigger points: vertical low back pain and front-of-hip pain from the primary hip flexor.

Erector Spinae: Erector spinae trigger points: referral below their own level, broad stiffness, a band across the back.

Gluteus Maximus: Gluteus maximus trigger points refer pain within the buttock, at the sacral edge, sit bone, and tailbone, worse with sitting and uphill walking.

Obturator Internus: Deep pelvic pain between the tailbone and the anus, rectal fullness, and pain down the back of the thigh.

Obturator Externus: Deep front-of-hip and groin pain that feels like the joint, worst turning the leg outward.

Quadratus Femoris and Gemelli: Deep low buttock pain beside the sit bone and down the back of the thigh, worst sitting and turning the hip.

Iliocostalis Lumborum: Low back on one side and the middle of the buttock together.

Longissimus Thoracis: Buttock pain sent down from a spot higher up the back.

Multifidi: Deep beside the spine at one level, and at the sacrum and tailbone.

Rotatores and Deep Paraspinals: Pain at the spine itself at one level, a single sore vertebra that catches when you turn.

Levator Ani and Coccygeus: Tailbone and sacral pain worst sitting, a rectal ache, and low back pain from the pelvic floor.

Thigh & Knee

Quadriceps: Vastus medialis and rectus femoris trigger points: front-of-knee and deep knee pain with aching in the lower anterior thigh.

Rectus Femoris: A deep ache in the front of the knee and under the kneecap, from a trigger point high at the hip.

Vastus Lateralis: Down the outer thigh to the outside of the knee, with a kneecap that sticks.

Vastus Medialis: The inner front of the knee and a knee that buckles without warning.

Vastus Intermedius: Pain in the middle of the front of the thigh, with a knee that is stiff to straighten after sitting.

Hamstrings: Hamstring trigger points and referral pattern: lower buttock and posterior thigh pain reaching the back of the knee.

Biceps Femoris: The back of the knee and up the outer back of the thigh, worst sitting.

Semitendinosus and Semimembranosus: Sit-bone pain that runs down the inner back of the thigh to the knee, worst on a hard chair.

Tensor Fasciae Latae (TFL): Tensor fasciae latae trigger points: hip joint pain at the greater trochanter running down the outer thigh, often mistaken for bursitis.

Adductor Group: Adductor longus and brevis trigger points: groin pain spreading down the inner thigh to the knee.

Sartorius: Sharp, tingling pain just under the skin along a line from the front of the hip to the inner knee.

Pectineus: Deep groin pain just below the crease of the hip that remains after the adductors have been treated.

Gracilis: A hot, stinging line along the inner thigh from the groin to the knee.

Popliteus: Popliteus trigger points: pain at the back of the knee, worse crouching and descending stairs.

Leg, Ankle & Foot

Gastrocnemius: Gastrocnemius trigger points and referral pattern: calf pain and instep ache, with night calf cramps in the documented territory.

Soleus: Soleus trigger points and referral pattern: heel pain, Achilles-line ache, and first-step morning pain often labeled plantar fasciitis.

Plantaris: The back of the knee running down into the upper calf.

Tibialis Anterior: Tibialis anterior trigger points and referral pattern: front-of-ankle pain and a line down the shin into the big toe.

Tibialis Posterior: Pain over the Achilles tendon that spreads to the calf, heel, and sole, worst on uneven ground.

Peroneal Group: Peroneal trigger points and referral pattern: outer-ankle pain behind and below the ankle bone that imitates a sprain that never healed.

Peroneus Tertius: The front and outside of the ankle and the outer heel, the ankle sprain that never healed.

Extensor Digitorum Longus: The top of the foot toward the smaller toes, with a foot that catches.

Extensor Hallucis Longus: The top of the foot at the base of the big toe, spreading into the toe.

Flexor Digitorum Longus: Across the ball of the foot into the four smaller toes, from a muscle deep in the calf.

Flexor Hallucis Longus: Under the big toe and the inner ball of the foot, from a muscle deep in the calf.

Deep Foot Muscles: Quadratus plantae and deep foot muscle trigger points: deep plantar heel pain, ball-of-foot ache, and inner-heel pain often labeled plantar fasciitis.

Extensor Digitorum Brevis and Extensor Hallucis Brevis: A coin-sized patch of pain on the top of the foot in front of the outer ankle, worse in a tight shoe.

Flexor Digitorum Brevis: Across the ball of the foot behind the middle toes, the pebble-in-the-shoe feeling.

Abductor Hallucis: The inner side of the heel and the inner edge of the foot, the heel pain that heel cups did not fix.

Adductor Hallucis: Deep pain across the ball of the foot from the big toe outward, with a numb-feeling forefoot.

Flexor Hallucis Brevis: Pain under the ball of the big toe, worst pushing off, the sesamoiditis with a normal X-ray.

Abductor Digiti Minimi (Foot): On the sole under the little toe, at the outer edge of the ball of the foot.

Interossei of the Foot: Along one toe, top and bottom, from the ball of the foot to the tip, with forefoot cramping.

Lumbricals of the Foot: Pain along the underside of one toe and the sole beneath it, with toe cramps at night.

A to Z

A

Abdominal Obliques: Abdominal oblique trigger points and referral pattern: heartburn-like upper abdominal pain and groin pain from the lateral abdominal wall.

Abductor Digiti Minimi (Foot): On the sole under the little toe, at the outer edge of the ball of the foot.

Abductor Hallucis: The inner side of the heel and the inner edge of the foot, the heel pain that heel cups did not fix.

Abductor Pollicis Longus and Extensor Pollicis: The back of the wrist on the thumb side and the back of the thumb, the de Quervain the splint did not fix.

Adductor Group: Adductor longus and brevis trigger points: groin pain spreading down the inner thigh to the knee.

Adductor Hallucis: Deep pain across the ball of the foot from the big toe outward, with a numb-feeling forefoot.

Anconeus: Pain at the outside of the elbow that stays at the elbow, worst pushing up from a chair.

B

Biceps Brachii: Biceps brachii trigger points refer superficial pain to the front of the shoulder, often misread as bicipital tendinitis.

Biceps Femoris: The back of the knee and up the outer back of the thigh, worst sitting.

Brachialis: Pain at the base of the thumb from the upper arm, with a numb back of the thumb.

Brachioradialis: Brachioradialis trigger points and referral pattern: outer-elbow ache running down the thumb side of the forearm to the base of the thumb.

C

Coracobrachialis: The front of the shoulder and a line down the back of the arm to the back of the hand, worst reaching behind the back.

D

Deep Foot Muscles: Quadratus plantae and deep foot muscle trigger points: deep plantar heel pain, ball-of-foot ache, and inner-heel pain often labeled plantar fasciitis.

Deltoid: Deltoid trigger points and referral pattern: pain felt locally in the shoulder cap itself, worse with movement.

Diaphragm: A stitch along the front lower ribs on a deep breath, and an ache at the top of the shoulder.

Digastric: Behind the ear and the upper neck, aching lower front teeth, and a lump in the throat when swallowing.

E

Erector Spinae: Erector spinae trigger points: referral below their own level, broad stiffness, a band across the back.

Extensor Carpi Radialis Longus and Brevis: Tennis elbow at the outer elbow and the back of the wrist and hand, with a grip that drops things.

Extensor Digitorum: Down the back of the forearm into the back of one finger, with stiff fingers in the morning.

Extensor Digitorum Brevis and Extensor Hallucis Brevis: A coin-sized patch of pain on the top of the foot in front of the outer ankle, worse in a tight shoe.

Extensor Digitorum Longus: The top of the foot toward the smaller toes, with a foot that catches.

Extensor Hallucis Longus: The top of the foot at the base of the big toe, spreading into the toe.

Extensor Indicis: The back of the wrist and the thumb side of the back of the hand, worst pointing and clicking.

F